Examine which operator values can be set to defaults

The following discussion from !586 (merged) should be addressed:

• @pursultani started a discussion: (+1 comment)

  discussion: We need to revisit the override values. IMO most of the them are in fact default values, for example all labels. A few value are actually overrides, including:

  • certmanager.install
  • gitlab-runner.install
  • global.ingress.*
  • global.serviceAccount.*
  • nginx-ingress.* except nginx-ingress.labels
  • {postgresql,redis,shared-secrets}.{serviceAccount,securityContext}.*
  • and maybe gitlab.gitlab-shell.service.type (I vaguely remember something about OpenShift)

With #927 (closed) we introduced a differentiation between operator default and operator override values.

Values now have the following priorities:

operator overrides > user values > operator default > chart default

Acceptance

• values which can be default values instead of override values were moved