2.1.2+1.19.2: Add some features and fix some bugs

- Added config option to set limit for number of graves existing at the same time
- Fix setting for grave creation in claims being cleared every time config loaded
- Guis no longer resets mouse position
- Added back button for list ui
- You can now fetch/move grave to players position by clicking new button in ui (requires `universal_graves.fetch_grave` permission for self, or `universal_graves.fetch_grave.others` for other players, op-only by default)