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/block/Anvil.php

@@ -23,12 +23,14 @@ declare(strict_types=1);
 
 namespace pocketmine\block;
 
-use pocketmine\block\inventory\AnvilInventory;
+use pocketmine\block\inventory\window\AnvilInventoryWindow;
 use pocketmine\block\utils\Fallable;
 use pocketmine\block\utils\FallableTrait;
 use pocketmine\block\utils\HorizontalFacing;
 use pocketmine\block\utils\HorizontalFacingOption;
 use pocketmine\block\utils\HorizontalFacingTrait;
+use pocketmine\block\utils\MenuAccessor;
+use pocketmine\block\utils\MenuAccessorTrait;
 use pocketmine\block\utils\SupportType;
 use pocketmine\data\runtime\RuntimeDataDescriber;
 use pocketmine\entity\object\FallingBlock;
@@ -39,13 +41,15 @@ use pocketmine\math\Vector3;
 use pocketmine\player\Player;
 use pocketmine\utils\Utils;
 use pocketmine\world\BlockTransaction;
+use pocketmine\world\Position;
 use pocketmine\world\sound\AnvilFallSound;
 use pocketmine\world\sound\Sound;
 use function round;
 
-class Anvil extends Transparent implements Fallable, HorizontalFacing{
+class Anvil extends Transparent implements Fallable, HorizontalFacing, MenuAccessor{
 	use FallableTrait;
 	use HorizontalFacingTrait;
+	use MenuAccessorTrait;
 
 	public const UNDAMAGED = 0;
 	public const SLIGHTLY_DAMAGED = 1;
@@ -80,12 +84,8 @@ class Anvil extends Transparent implements Fallable, HorizontalFacing{
 		return SupportType::NONE;
 	}
 
-	public function onInteract(Item $item, Facing $face, Vector3 $clickVector, ?Player $player = null, array &$returnedItems = []) : bool{
-		if($player instanceof Player){
-			$player->setCurrentWindow(new AnvilInventory($this->position));
-		}
-
-		return true;
+	protected function newMenu(Player $player, Position $position) : AnvilInventoryWindow{
+		return new AnvilInventoryWindow($player, $position);
 	}
 
 	public function place(BlockTransaction $tx, Item $item, Block $blockReplace, Block $blockClicked, Facing $face, Vector3 $clickVector, ?Player $player = null) : bool{