Add the bundle_stream variable for job templates

The bundle_stream variable will allow to easily set the
bundle stream from the profile file for the different
job templates.

This commit also sets the value of such a variable to
the new stream: /public/personal/apertis-validator/

Reviewed-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D2684