The main goals of this patch are to:
- Improve the exception handling in Aegis and the way we present errors messages
to the user when they occur.
- Write exception stack traces to the log in more places, so that the ADB logs
we ask for from our users when reporting bugs become more useful.
- Reduce the amount of times we throw a RuntimeException, particularly when an
Android Keystore operation fails.
Achieving the above goals ended up resulting in a very large refactor. The
intro and unlock flow of the app need to be retested entirely.
We decided on calling the state file the "vault" a while back. This patch makes
the naming consistent across the codebase. I left "DatabaseImporter" classes
alone, because I'm not sure what a better name for those would be.
This also fixes an issue with the use of the Iconics library where it was
initialized twice. I also removed the dependency to [AndroidX Preference
eXtended](https://github.com/takisoft/preferencex-android), as there don't seem
to be any issues with using the vanilla AndroidX preference library anymore.
This adds an option to automatically lock the app when:
* The back button is pressed
* The device is locked
It's the first step towards implementing #7
