parsoidsvc using multigit script

The parsoidsvc jobs are going to be triggered by changes made against
two projects:
  mediawiki/services/parsoid
and
  mediawiki/services/parsoid/deploy

The multiple git macro would not let us apply the patch (ZUUL_REF) to
the proper project, so instead we are now using a tiny shell script that
takes care of cloning/refereshing repositories and applying the patch on
the repo that triggered the change (ZUUL_PROJECT).

Change-Id: Iaa90b840f452f4415e7a59d7012c084aa7587e5b