Add smart watch / wear OS support

[rolandgeider]

(idea for the future)

At least the gym mode view would fit perfectly onto a smart watch display with little changes to the UI and would be really useful. For wear OS there is a package available but till the sync between phone and watch isn't solved, we won't be able to do much since we would need to individually login on the phone itself.

https://verygood.ventures/blog/building-wear-os-apps-with-flutter-a-very-good-guide
https://medium.com/@Toglefritz/create-a-cross-platform-flutter-app-for-android-and-wear-os-and-others-267d142867c0

[rolandgeider]

See also https://pub.dev/packages/watch_connectivity

[rolandgeider]

Seems https://pub.dev/packages/wear is not being maintained anmore, the replacement seems to be https://pub.dev/packages/wear_plus