Improve item navigation / visibility on mercs with controller

1. Navigating items on mercs with a controller is not working optimal due to how the analog stick selects items.

Solution: Auto navigate through all items from left to right, instead of manually selecting them.

2. When modifying items on an existing merc, I need to use triangle an manually drag the item over. There is also no comparison mode

Solution: When merc inventory is open, let me use X to equip items on mercs. Also, add compare mode to merc items.

Additionally, it would be great if you could add rarity border-colors to items.

Edit: Also, let me check items using the mouse