jenkins: update openstack-mkcloud job configuration

Sync job configuration with the current version used in river.suse.de

Changes made:

* Remove `WITHTEMPEST` parameter
* Add `tempestoptions` parameter
* Add `networkingmode` parameter
* `cephvolumenumber` changed from `2` to `1`
* Timeout changed from 90 minutes to 4 hours (perl alarm)
* Added `nodenumber`, `networkingplugin` and `tempestoptions` parameters to
  the name of the build
mkcloud: Add 9p fs for local repos to admin node

Add $localreposdir_src var and if available add 9p filesystem to admin node
so in the future local repositories can be used for the admin node.
This is still WIP but with this commit at least the 9p fs is available
in the VM and the var $localreposdir_target is exported for
the sshrun of qa_crowbarsetup.sh.
qa_crowbarsetup: Mount local repos dir via 9p

If requested via $localreposdir_src, mount $localreposdir_target via 9p
inside the crowbar VM. This can be used later to use local repositories.
Useful to minimize network traffic.
qa_crowbarsetup: Add local repos support

When $localreposdir_target is set, local repositories are used for crowbar
managed nodes and to setup the crowbar node itself.