* Enforce lint cleanliness when building
The volume of lintable issues is growing. To stem the tide:
1. Add `app/lint-baseline.xml`, which contains the current set of lint issues.
Any issue appearing here will not cause the build to fail.
2. Move lint configuration settings in to `lint.xml`.
3. Update the lint configuration so that any issue (i.e., any issue not
in lint-baseline.xml) causes a build failure.
4. Add the lint tasks as depedency when assembling an APK, to ensure the
lint checks are run.
* lint: Convert launcher images to webp
* Move lint.xml location
* Don't lint when assembling
* Update baseline
