Inventory panel rework

[Arcanorum]

Task description

As per #30 an inventory management panel is needed to present the new way that items are represented.
This would be a panel that presents the players character's current items in a grid, from which the player can select an item to do something with.

The following draft design wireframe illustrates the core functionality flow.

Equippable items should show options to

• Equip: Adds the item to the player's hotbar and equips it
• Add to hotbar: Adds the item to the player's hotbar

Consumable items should show options to

• Use once: Uses/consumes/activates the item once
• Add to hotbar: Adds the item to the player's hotbar

In addition to the above options, a drop button should be shown, that works slightly differently depending on the item type selected.

• Stackable: Shows options for what quantity of the stack to drop.
• Non-stackable: Drops the item.

References/notes

The server will need to provide the player's current inventory when they join the game world, and update it whenever the player's inventory state changes.