Potentially fixes some other issues we didn't know about too...
This just stops anything interfering with creating slides,
and stops fetching the slides halfway through processing
The theme combo box did not show when the currently rendered item
doesn't support the service/song theme levels.
This changes the theme combo box to use the theme level from the
settings rather than the currently rendered item.
- Refactor wizard pages into external page components
- Refactor form labels into a central label with the alignment already set
- Fix some tests
- Write more tests
- Fix the theme preview generation to happen in the right place after the First Run Wizard
- Mock the settings in the DisplayWindow tests to see if that helps the Arch runner
- Add tests for the new form
