Separate UI and backend actions
See https://redux.js.org/advanced/async-actions
In general there should be:
- UI
- Select RepositoryList
- Select TagList
- Select TagDetails
- Invalidated
X
- Backend
- Fetch RepositoryList
- Fetch TagList
- Fetch Manifest
- Fetch Image
- Receive
X
This uses revised names, see #6 (closed).