fixed theme update, change theme should now propagate through the entire app

IPT

Routing

• routing should work fine now for both android / web
• fixed needed double click on sign in / out , Closes #15 (closed)
• there should be no way now to get to the login screen when logged in, Closes #16 (closed)
• made log in state persistent through the session lifecycle, Closes #41 (closed)
  • not a direct fix, but it's sufficient enough
  • when closing/killing the app on android, the user will still be logged in

Theming

• fixed issue with poll-view not reacting to theme change
  • internally it uses bloc in favor of provider (no idea why it works now)
  • switched from shared_preferences to hydrated_bloc
    • there compile errors when using android sdk <= 21

Language

• replaced more const texts with language switch
  • added more translation keys
  • made language selection persistent
  • added system option to automatically pick current default lang (doesn't work on web)

Logging

• replaced all print and debugPrint with corresponding logger statements

Docker backend

• added dockerBuild.sh and dockerRun.sh within backend/ for running it

Refactoring

• removed a bunch of dead code
• optimized imports
• added utils/commons.dart to reduce overall imports

Location picking

• fixed issue where overlay is absorbing drag events on android

various stuff

• fixed android particpate poll/ my poll view not loading due to casting error
• fixed google map view on android
• added custom painter for drawing dashed circles
• added basic firebase rules, incomplete since some require backend validation

bugs

• the enviroment profile 'local' is broken, due to missing impl of uidstream
• the language asset loaded throws errors on login screen, due to missing english translations (doesn't wanna load the default file)
  • as a quickfix strings.json where renamed strings-en.json
  • theres a path concatenation issue, where the plugin want to load assets/assets/... which obviously doesn't exist, however fixing it for the development enviroment will break the app building..
• when the theme of the android device is set to dark, some text is not readable
• on android, drag events dont bubble to the map view when having one outside and one inside the overlay