qt-jenkins-deploy.pl: support cron-based triggers
qt-jenkins-deploy.pl: support cron-based triggers

There are a few special projects which are triggered periodically; add
support for this to the configuration file.

It might also be useful to mix periodic builds with gerrit-triggered
builds for the same project, to ensure that projects are regularly
tested even if they have no incoming changes.

Change-Id: I5e36a1bd2c787fef43c7a7dd98dd0e6fdf7ca4de
Reviewed-by: Janne Anttila <237e68234a327a5775cffcea05af0474ad4190b9@digia.com>
Reviewed-by: Sergio Ahumada <27ca633ce817d1c3858ceeac3c99febb78411853@digia.com>

tsarajar/qtqa,tsarajar/qtqa,tsarajar/qtqa,tsarajar/qtqa