[Engine] Code cleanup
[Client] Cleanup player movement code
[Client] Fetching position of player and not of the character to hide the upper levels
[Client] Defined commands to pickup one or many items
[Client] Client dragging on the tile of the own character now picks the item up
[Client] Added pickup all hotkey
[Client] Updated item move command map->map
[Client] Updated item move command map->inventory
[Client] Updated item move command map->showcase
[Client] Updated player turn command
[Client] Added button to the inventory that triggers the pickup of all items