Separate inventory holder info from container & player inventories (#6533)

This PR breaks the cyclic dependency between `Inventory` and its holder, which unblocks a lot of new developments.

### Related issues & PRs
- Fixes #5033
- Removes a blocker for #6147 (which in turn means that async tasks will eventually be able to work with tiles)
- Removes a blocker for #2684

## Changes
### API changes
- `Player->getCurrentWindow()` now returns `?InventoryWindow` instead of `?Inventory`
- `Player->setCurrentWindow()` now accepts `?InventoryWindow` instead of `?Inventory`
- `InventoryWindow` introduced, which is created for each player viewing the inventory, provides decorative information like holder info for `InventoryTransactionEvent`, and is destroyed when the window is closed, eliminating cyclic references
- Added:
  - `player\InventoryWindow`
  - `player\PlayerInventoryWindow` - wraps all permanent inventories of Player with type info for transactions
  - `inventory\Hotbar` - replaces all hotbar usages in `PlayerInventory`
  - `Human->getHotbar()`
  - `Human->getMainHandItem()`, `Human->setMainHandItem()`, `Human->getOffHandItem()`, `Human->setOffHandItem()`
  - `block\utils\AnimatedContainerLike` & `block\utils\AnimatedContainerLikeTrait` (for chests, shulkerboxes, etc)
  - `block\utils\Container` & `block\utils\ContainerTrait` for blocks containing items (chests, etc)
  - `block\utils\MenuAccessor` implemented by all blocks that can open inventory menus
  - `block\utils\MenuAccessorTrait` used by blocks with menus but without inventories (anvils, crafting tables etc)
- Removed:
  - `inventory\DelegateInventory` (only used for ender chests)
  - `inventory\PlayerInventory`,
  - `inventory\PlayerOffHandInventory`,
  - `inventory\PlayerCraftingInventory`,
  - `inventory\PlayerCursorInventory` - these have all been internally replaced by `SimpleInventory` & they will appear as `PlayerInventoryWindow` in transactions (check `getType()` against the `PlayerInventoryWindow::TYPE_*` constants to identify them)
  - `block\inventory\AnimatedBlockInventoryTrait`, (blocks now handle this logic directly using `AnimatedContainer` and `AnimatedContainerTrait`)
  - `block\inventory\BlockInventoryTrait`,
  - `block\inventory\BlockInventory`
- Most `BlockInventory` classes have been transitioned to `InventoryWindow` wrappers
- Tiles now all use `SimpleInventory` internally (no cyclic references) except for `Chest` (which uses `CombinedInventory`, without holder info)
- `InventoryOpenEvent` and `InventoryCloseEvent` now provide `InventoryWindow` instead of `Inventory` (to provide type information)
- `InventoryTransaction` and `SlotChangeAction` now provide `InventoryWindow` instead of `Inventory`
- Renamed `TransactionBuilderInventory` to `SlotChangeActionBuilder`
- `TransactionBuilderInventory->getBuilder()` now accepts `InventoryWindow` instead of `Inventory`
- `DoubleChestInventory` superseded by `CombinedInventory` - this new class allows combining any number of inventories behind a single object; mainly used for double chests but plugins could use it to do lots of fun things

### Impacts to plugins
Plugins can now do the following:
```php
$block = $world->getBlockAt($x, $y, $z);
if($block instanceof MenuAccessor){
    $block->openToUnchecked($player);
}
```
As compared to the old way:
```php
$tile = $world->getTileAt($x, $y, $z);
if($tile instanceof Container){
    $player->setCurrentWindow($tile->getInventory());
}
```

#### Advantages
- No tile access needed
- Works for menu blocks without inventories as well as container blocks
- Less code

### Behavioural changes
Inventories no longer keep permanent cyclic references to their holders.

## Backwards compatibility
This makes significant BC breaks. However, all changes are able to be adapted to and the same amount of information is present on all APIs and events.

## Follow-up
- Implement #6147 
- Support inventory inheritance when copying blocks from one position to another

src/inventory/transaction/SlotChangeActionBuilder.php

@@ -0,0 +1,120 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+ */
+
+declare(strict_types=1);
+
+namespace pocketmine\inventory\transaction;
+
+use pocketmine\inventory\BaseInventory;
+use pocketmine\inventory\Inventory;
+use pocketmine\inventory\transaction\action\SlotChangeAction;
+use pocketmine\item\Item;
+use pocketmine\item\VanillaItems;
+use pocketmine\player\InventoryWindow;
+
+/**
+ * This class facilitates generating SlotChangeActions to build an inventory transaction.
+ * It wraps around the inventory you want to modify under transaction, and generates a diff of changes.
+ * This allows you to use the normal Inventory API methods like addItem() and so on to build a transaction, without
+ * modifying the original inventory.
+ */
+final class SlotChangeActionBuilder extends BaseInventory{
+
+	/**
+	 * @var \SplFixedArray|(Item|null)[]
+	 * @phpstan-var \SplFixedArray<Item|null>
+	 */
+	private \SplFixedArray $changedSlots;
+
+	public function __construct(
+		private InventoryWindow $inventoryWindow
+	){
+		parent::__construct();
+		$this->changedSlots = new \SplFixedArray($this->inventoryWindow->getInventory()->getSize());
+	}
+
+	public function getInventoryWindow() : InventoryWindow{
+		return $this->inventoryWindow;
+	}
+
+	protected function internalSetContents(array $items) : void{
+		for($i = 0, $size = $this->getSize(); $i < $size; ++$i){
+			if(!isset($items[$i])){
+				$this->clear($i);
+			}else{
+				$this->setItem($i, $items[$i]);
+			}
+		}
+	}
+
+	protected function internalSetItem(int $index, Item $item) : void{
+		if(!$item->equalsExact($this->inventoryWindow->getInventory()->getItem($index))){
+			$this->changedSlots[$index] = $item->isNull() ? VanillaItems::AIR() : clone $item;
+		}
+	}
+
+	public function getSize() : int{
+		return $this->inventoryWindow->getInventory()->getSize();
+	}
+
+	public function getItem(int $index) : Item{
+		return $this->changedSlots[$index] !== null ? clone $this->changedSlots[$index] : $this->inventoryWindow->getInventory()->getItem($index);
+	}
+
+	public function getContents(bool $includeEmpty = false) : array{
+		$contents = $this->inventoryWindow->getInventory()->getContents($includeEmpty);
+		foreach($this->changedSlots as $index => $item){
+			if($item !== null){
+				if($includeEmpty || !$item->isNull()){
+					$contents[$index] = clone $item;
+				}else{
+					unset($contents[$index]);
+				}
+			}
+		}
+		return $contents;
+	}
+
+	public function getMatchingItemCount(int $slot, Item $test, bool $checkTags) : int{
+		$slotItem = $this->changedSlots[$slot] ?? null;
+		if($slotItem !== null){
+			return $slotItem->equals($test, true, $checkTags) ? $slotItem->getCount() : 0;
+		}
+		return $this->inventoryWindow->getInventory()->getMatchingItemCount($slot, $test, $checkTags);
+	}
+
+	/**
+	 * @return SlotChangeAction[]
+	 */
+	public function generateActions() : array{
+		$result = [];
+		$inventory = $this->inventoryWindow->getInventory();
+		foreach($this->changedSlots as $index => $newItem){
+			if($newItem !== null){
+				$oldItem = $inventory->getItem($index);
+				if(!$newItem->equalsExact($oldItem)){
+					$result[] = new SlotChangeAction($this->inventoryWindow, $index, $oldItem, $newItem);
+				}
+			}
+		}
+		return $result;
+	}
+}