Enable customization via configuration Activity

[hoppjan]

Android allows users to customize widgets.

To do so, we will need regular Jetpack Compose (not Glance, which does the widget's RemoteViews).

Next steps:

• [x] add Jetpack Compose dependencies
• [x] add a proof-of-concept Activity that can configure the widgets later
• [x] add infrastructure for Jetpack Compose theming
• [x] add customization options in the Activity and make it actually change the widget

  • 9 filtering for specific allergens etc.

  • [x] #21 allow the user to show the date in the widget, on which the meals are served
  • [x] maybe more?
• [x] profit!