Aa-fleetfinder

Added

- Spanish translation

Fixed

- Bootstrap CSS fix

Added

- Footer to promote help with the app translation

Changed

- Ukrainian translation improved

Changed

- Use Django's native message system instead of forcing our own
- Translations improved
- Task code cleaned up
- Error tracking for ESI fleets moved to the DB instead of being cached by Redis, as
Redis was too unreliable and there was a good chance the task stopped working
properly.

Changed

- Moved the build process to PEP 621 / pyproject.toml

Added

- Russian translation