Ability to disable unused controllers

[mikkoc]

Hello,
I would like to request two nice-to-have features.

1. Allow to either disable certain controllers, or only enable certain controllers (preferred). We only use Kafka, so we're not interested in all the other stuff that the Operator supports. Expose this ability via Helm.
2. Allow to configure LOG_LEVEL of the Operator via Helm values.

Thanks

[mikkoc]

I realise that the 1st request might be partially covered by #380

[vmyroslav]

@mikkoc
Thanks for the ideas. I can't guarantee the first one for now, but we can add the LOG_LEVEL configuration. I'll post updates here.