Fix styling on mobile for various UIs

This isn't an exhaustive fix, just working on some pressing things:

• Inventory should use screen space better
• Stash should use screen space better
• HUD, Menu, Chat Button and Spells should move slightly closer to the edges to afford the game more space

Also done:

• Removed the stats divs from uiInventory and uiStash since these haven't been used in a very long time