Publishing Hallo Welt internal REL2_22

This is the current state of "Hallo Welt" internal REL2_22 branch. It has
to be made available in the REL1_22 branch of the WMF. By this a end user
can download the proper version using the extension distributor on
mediawiki.org

Change-Id: Ibf1e3bfc35473b4d90d4d0b48d27ec0dabfbd446