The base job template is responsible for controlling how we kick off
testing on our various branches. Rename and extend the
custom_runner_template so we can take advantage of all that control.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20230228190653.1602033-7-alex.bennee@linaro.org>