Keep helm repositories in sync across multiple pipeline instances

[lpuskas]

Is your feature request related to a problem? Please describe.
Helm repositories in pipeline are updated through api calls. The state of helm repositories should be in sync across pipeline instances

Describe the solution you'd like to see
Helm repositories should transparently be synchronised on all pipeline instances:

• maintain a hash of the repository related files in the database (indexfile + chart file)
• on every operation check the hash generated from the file system and the one stored in the database
• perform an update if appropriate
• update the hash in the database with the one generated from the filesystem after the update id done
• also store a hash in. the database when a new repository is added to the filesystem

[sagikazarmark]

I wonder if rewriting the helm repository management to use the database would be easier/more stable than an arbitrary solution built on top.