Rename VALIDA_REPO_BREEDS to REPO_BREEDS.
Move virt types list into validate.py.
Remove Monit support from Cobbler core.

Managing services and their configuration should really be
done by a configuration management system (eg. Puppet).
Docs: document the Monit removal in the release-notes.
Merge pull request #1226 from jmaas/master

Remove monit support and minor repo_breeds refactoring