Replace old onboarding with the new one

[TimoPtr]

Description

A new onboarding has been made since few months already and we need to release it.

Additional context

We need to remove the code related to the old onboarding. Migrate the code that is part of :onboarding that is actually part of the :app Remove all the if/else that is hiding the new onboarding.

Before doing this we need (in order)

• [x] Get an update approved by Google
• [x] Release a new version and have it approved by Google that removes the support for Android 5

After that (or before if it doesn't impact the release)

• [x] Modify the WebviewActivity so that it asks for Notification and Battery optimization permissions https://github.com/home-assistant/android/pull/6094 and https://github.com/home-assistant/android/pull/6095.
• [x] Support minimal flavor in the new onboarding https://github.com/home-assistant/android/pull/5982
• [ ] Update documentation (https://github.com/home-assistant/companion.home-assistant/pull/1264) and update all the links in the onboarding https://github.com/home-assistant/android/pull/6151
• [ ] Blocking logic based on allowInsecure flag needs to be implemented
  • [ ] Webview- https://github.com/home-assistant/android/pull/6103
  • [ ] Background - https://github.com/home-assistant/android/pull/6148
  • [ ] Websocket should use getFlow() and disconnect when changing URL https://github.com/home-assistant/android/pull/6150
  • [ ] Handle no network on getFlow() to emit proper state and show proper error in Webview
• [ ] Migration for old setup with insecure connection https://github.com/home-assistant/android/pull/6097
• [x] Minimal flavor needs to be injected instead of checking the package name https://github.com/home-assistant/android/pull/6030
• [x] Review all the todos in onboarding https://github.com/home-assistant/android/pull/6116
• [x] Rework OnboardApp https://github.com/home-assistant/android/pull/6115
• [x] Cleanup strings https://github.com/home-assistant/android/pull/6117