Block: Clean up internal constructor inconsistencies

I don't dare look how big this commit is or how many bugs it introduced...

src/pocketmine/block/BrownMushroom.php

@@ -25,12 +25,6 @@ namespace pocketmine\block;
 
 class BrownMushroom extends RedMushroom{
 
-	protected $id = self::BROWN_MUSHROOM;
-
-	public function getName() : string{
-		return "Brown Mushroom";
-	}
-
 	public function getLightLevel() : int{
 		return 1;
 	}