==Benefits
(1) No more hassling around with updating java-mwapi version numbers in the pom.xml of the lib and the app's build.gradle file. Lately we basically end up making one or two changes but then have to bump the version number of the lib so we can release our app, and have repeatable builds.
(2) No more uploading of the java-mwapi artifact to our team repo, which was clunky.
(3) Makes it easier for -Fdroid or others to build our app
Sidenote: T103051 could be an alternative to tackle (2) and (3).
==Implementation ideas
[] We could pull java-mwapi into the app as Git submodule.
[] A Gradle module for the java-mwapi library would be good.
[] Consider making JUnit tests runnable from Gradle.
[] Remove dependency in ./wikipedia/build.gradle and usage of https://tools.wmflabs.org/android-maven-repo in ./build.gradle.