Feat: add a consumer group role configuration

[ludovic-boutros]

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  Fix: RBAC - Add possibility to change consumersGroup role #511

[purbon]

This model is used for both RBAC and ACLs permissions and might be even used later on for other integrations (I know some people who tried to do it with Ranger, for example).

I think we should not be using here:

• The variable name as group-role, as with ACLs there are no roles per se.
• The default value as RESOURCE_OWNER as it is Confluent RBAC dependant.

What do you think?

[ludovic-boutros]

I agree, I will try to see how to deal with this point.

[ludovic-boutros]

If we add a level called "rbac" in the configuration of a consumer, would it be okay for you ?

consumers:
     - principal: "Group:CONSUMER_READ"
       rbac:
           role: DeveloperRead
     - principal: "Group:CONSUMER_VIEW"
       rbac:
            role: DeveloperRead

We should do the same in the schema configuration I guess, even if currently, ACLs are only available with RBAC for schemas.
WDYT ?

[ludovic-boutros]

@purbon kind reminder on the proposal :)