This change adds a new lint `android-format` which enforces formatting of Java
code using google-java-format.

To run the lint simply run:

./mach lint -l android-format

This command also support automatically fixing all errors running by adding
--fix:

./mach lint -l android-format --fix

This change also removes all the formatting-related checkstyle checks which are
now implicitly enforced by the formatter.

Differential Revision: https://phabricator.services.mozilla.com/D127734