AppSupport lockscreen support

This patch improves Android AppSupport to allow setting a lockscreen PIN. This is useful for Android apps which refuse to run if a PIN isn't set (such as Rail Planner).

After installing the patch, you should restart Android AppSupport.

Afterwards, you can set an Android PIN by going to: Settings -> Android AppSupport -> press on "Android version" 5 times -> Security -> Screen lock. The PIN will only be seen by Android apps, it won't affect the Sailfish lockscreen.

The code is available at: https://codeberg.org/nick8325/appsupportkeyguardstub