Added manual triggering of pre-release-gerrit

Added manual triggering of pre-release-gerrit

Introducing parameters to the job makes it possible to trigger it
manually by 'Build Now' link and remotely.

This change implements triggering pre-release workflow manually.

I've added 3 parameters for the job:
 GERRIT_PROJECT, GERRIT_REFNAME and GERRIT_NEWREV

GERRIT_NEWREV can be set to the same value as GERRIT_REFNAME to trigger
the workflow. Usually it's submit tag.

Change-Id: Ic373beb4238016170130a8cb3ca156ea6dcffd43
Signed-off-by: Ed Bartosh <eduard.bartosh@intel.com>