[Feature] Equipment

This pull request adds equipment support to RPGKeeper. The features include:

- [ ] Ability to add Mundane Items (to Character)
- [ ] Ability to edit Mundane Items
- [ ] Ability to remove Mundane Items from character
- [ ] Ability to add Magic Items (to Character)
- [ ] Ability to edit Magic Items
- [ ] Ability to remove Magic Items from character
- [ ] Ability to add Armor (to Character)
- [ ] Ability to edit Armor
- [ ] Ability to remove Armor Items from character
- [ ] Ability to add Shields (to Character)
- [ ] Ability to edit Shields
- [ ] Ability to remove Shields Items from character
- [ ] Ability to add Weapons (to Character)
- [ ] Ability to edit Weapons
- [ ] Ability to remove Weapons Items from character

(Magic items include Implements, Neck slot items, Arm slot items, Hand slot items, Waist slot items, Head slot items, Foot slot items, Rings, Potions, Wondrous items)

Once that checklist is complete, this PR will be ready for merging.