OLM installation doesn't support setting flags for the operator

[hoptical]

Is your feature request related to a problem? Please describe.
I want to install vault-secret-operator through OLM (OperatorHub). I need to set some parameters available in the helm chart, such as PersistenceModel. However, since it's configured as a flag for the operator and operator doesn't support ARGS as environment variable, it seems that we can't set such configuration in the OLM mode.

Describe the solution you'd like
Being able to set manager flags as environment variables. This can either be done via a separate env for every flag or supporting ARGS as an environment variable.

Describe alternatives you've considered
Nothing specific.

Additional context

[tvoran]

Hi @hoptical, thanks for pointing this out. I think #551 should take care of this for OLM.