Be more helpful when no versions available due to mismatching signatures.
This is surprisingly common, especially for new F-Droid users who are trialling F-Droid to see if they want to make the switch from Google Play to F-Droid. As such, we should make the UX as good as possible. This does the following:
- If no versions are available, tell the user why instead of showing an empty expandable "Versions" list. Either:
- "No versions with compatible signature"
- "No versions compatible with device"
- Upon tapping this brief explanation, show the user a more in depth explanation.
- When showing the explanation, also offer to take them to settings so they can enable "Incompatible versions".
- If "Incompatible versions" is enabled, tell the user if the incompatible-ness is due to incorrect signatures.
Fixes #1115 (closed).