Officially support labels for pipelines and agents to improve pipeline picking.
* add pipeline labels
* update, improve docs and add migration
* update proto file
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closes#304 & #860
Resolve some todos in server/model:
* Move persistent queue into its own package
* Create Types: StatusValue, SCMKind, RepoVisibly
* Rename struct Repo fields: SCMKind, IsSCMPrivate
* Move cncd/{logging,pubsub,queue}/ to server/{logging,pubsub,queue}/
* Update REAMDEs and include history
Co-authored-by: Anbraten <anton@ju60.de>
Co-authored-by: Anbraten <anton@ju60.de>