Easier option to change dns operator log level

#### Problem

Right now the only way to enable debug logs in DNS Operator is to change the deployment or DNS Operator CSV to have `--zap-log-level=debug` flag. Some new option for easier log level configuration on cluster would be nice to have

#### Solution proposals
1. Configure from DNS Operator controller configmap
2. Set subscription env variable
3. DNS Operator CRD (probably not)

Start by examining how the DNS Operator deployment, DNS Operator CSV, controller configmap, subscription environment, and DNS Operator CRD expose configuration. Compare the three proposed approaches and define which cluster-level log-level workflow should be supported; done means the chosen configuration can enable debug logs without editing the deployment or CSV.

Written by the indexing model from the issue text.