Each of these updates is required for the following update, and the
final one allows us to use 'record'.
The target SDK version is set to 33, matching the Android app.
- Switch to the modern maven-publish plugin.
- Bump the Android target SDK version to 30 to match the app.
(The minimum is still 19.)
- Bump the Java source compatibility version to 1.8.
- Bump the Android command line tools used in Docker to match the app.
- Bump the JDK used in Docker to OpenJDK 11, matching the app.
- Switch to the androidx testing libraries for emulator testing.
- Drop unused trove4j Gradle plugin.
- Lots of cleanup and refactoring.
