Add an option to enable local Docker registry

[arun-gupta]

Add an option that allows to setup a local Docker registry in the cluster. This allows a simpler workflow OOTB.

[tirumaraiselvan]

I think it will be a nice add-on to give a test docker registry in-built. Although, the user may still need to configure persistent volume for the registry. So the question becomes, is that really a simpler workflow?

@coco98 @shahidhk

[pdomagala]

@arun-gupta Have you tried setup gitkube with local docker registry in your cluster? Have you had any problems with this? I can't manage with SSL and basic auth on it.

[tirumaraiselvan]

@pdomagala Do you mean not specifying a remote docker registry? If so, that means it would work only for a single node cluster.