ruby1.9.3 lint jobs for some repositories

Ruby lint should run after every patch set submission for all
repositories that contain Ruby code.

Jobs created:

mwext-CirrusSearch-ruby1.9.3lint
mwext-Flow-ruby1.9.3lint
mwext-Translate-ruby1.9.3lint
mwext-TwnMainPage-ruby1.9.3lint
mwext-VisualEditor-ruby1.9.3lint
mwext-Wikibase-ruby1.9.3lint

Bug: 56156
Change-Id: I59e2fc1a007ba1585cb4bb2647c6104a474597a2