automation to include completed translations via merge requests

@pmmayero In terms of localization automation work, I think a good place to start would be tools/pick-complete-translations.sh. Here's my current idea: that could be scheduled to run once a day in a CI job. It would generate a merge request with the results. As for auth, it could be either a CI_JOB_TOKEN or an SSH Deploy Key. Then use GitLab Push Options to create the merge request. This is how it is done in checkupdates. I'm open to ideas for simplification too.