Always execute migration 9999 (can be used to fix things manually)
Optimized meal plan navigation / date range filtering
Prepared next release
Pulled translations from Transifex
Various code optimizations
* Locales: use http-accept-language or "language"-cookie
* Add user-setting "locale"
Rename CULTURE to DEFAULT_LOCALE
* Use LocaleMiddleware also in dev mode
* CORS: don't require authentication on OPTIONS
* Use a standard user-settings-control and start a new generic user settings page, not a separate page for the locale setting
* Fixed (broken by myself) link-return handling
* Clarify language settings
* Removed unneeded files
* Better user settings icon
* Added localization hints
Co-authored-by: Bernd Bestel <bernd@berrnd.de>