Some users understandably get confused when they try to import a backup
file from a different 2FA app during the intro and then get greeted
with an error dialog.
This changes the button text to "Import Aegis vault" and adds a small
hint text in the hope that this makes the limitations of the intro more
clear to the user.
<img width="200" src="https://alexbakker.me/u/jzhh3bk30w.png" />
Apparently ``getQsTile()`` can return null, which resulted in a crash.
Reported through the Google Play Console:
```
Exception java.lang.NullPointerException: Attempt to invoke virtual method 'void android.service.quicksettings.Tile.setState(int)' on a null object reference
at com.beemdevelopment.aegis.services.LaunchAppTileService.onStartListening
at android.service.quicksettings.TileService$H.handleMessage (TileService.java:488)
at android.os.Handler.dispatchMessage (Handler.java:106)
at android.os.Looper.loopOnce (Looper.java:205)
at android.os.Looper.loop (Looper.java:294)
at android.app.ActivityThread.main (ActivityThread.java:8177)
at java.lang.reflect.Method.invoke
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:552)
at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:971)
```
This introduces a new (optional) 'name' field for iconpack icons. It
will be used to describe the icon in the icon selection dialog. If it is
not present, the name of the icon will be derived from the filename,
like before. Using this new field allows usage of more exotic characters
in the icon name that are not allowed in a filename.
This adds support for Authenticator Pro's latest backup format changes.
The format of the content itself has not changed as far as I can tell, but
they do use a different cipher and KDF now: AES GCM and Argon2id,
respectively.
The memory cost is statically set at 64MiB. I suspect that this may
cause OOM situations on some lower-end devices, but we'll see, not much
we can do about that right now without making more changes.
