Add .gitreview to allow contributors submit changes
Add .gitreview to allow contributors submit changes

When cloning the repo there is no .gitreview so it is not possible to submit
changes easily via `git review`.

Change-Id: I5e9d084f85f11db9fccd031507c8b0a53912f967

wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps