Improve location/category picker UX #11

It's currently impossible to choose a category or location for an item without knowing which categories/locations exist.

Also, adding a category or location on-the-fly from the item creation screen should be possible.

Improve category/location dropdowns
Add button next to dropdowns for creating category/location on the fly

It's currently impossible to choose a category or location for an item without knowing which categories/locations exist. Also, adding a category or location on-the-fly from the item creation screen should be possible. - [x] Improve category/location dropdowns - [ ] Add button next to dropdowns for creating category/location on the fly

Label Meilensteine

Improve location/category picker UX #11