Redesign Inventory System and move it out of the entity Card

[sEver]

Use cases:

• [x] Opening my own inventory
  • [x] equipping items
  • [x] dropping item
• [x] Looting items from the floor/dropping them on the floor

Shortest possible path:

• [x] Add inventory button to EntityCard
• [x] Clicking the button, opens the inventory Panel.