disable non-functional repositories in production

[dietervu]

E.g. National Library of Medicine has a known issue. Would be nice if we could mark it as such in the repo metadata so that it does not show up in the beta and production instance. Showing it in alpha is fine.

[MichalGawor]

Currently no mechanism to disable/enable configurations, only changing its physical location ourside of repo configurations in DOGlib. Can be addressed in next iteration as multiple new repositories have been requested to be added.