Unable to install on Android 9 (LineageOS 16)

The described method in the readme (copying the apk to /priv-app) does not work anymore on Android 9 due the permission-whitelist enforcing [ASOP docs](https://source.android.com/devices/tech/config/perms-whitelist). As a result of this, **your phone won't boot** if you just copy the apk to `priv-app`!
As far as I understand, the issue should be solvable by creating a matching priv-app-permission.xml file in `/etc/permissions`.

I'm willing to contribute the required changes to the readme - however since I'm pretty unfamiliar with the android stack a need a bit more information:
- What would be the package name(s) and their required permissions
- Is there any kind of signature stuff involved?

Start with the README section describing installation by copying the APK to /priv-app, then consult the linked AOSP permission-whitelist documentation. Identify the package names, required permissions, and any signature requirements before updating the installation instructions. Done means the README explains the Android 9 procedure without risking a boot failure.

Written by the indexing model from the issue text.