Refactor snapshot operator

As OpenShift developer I want cluster-csi-snapshot-controller-operator to use existing controllers in library-go, so I don’t need to maintain yet another code that does the same thing as library-go.

• Check and remove manifests/03_configmap.yaml, it does not seem to be useful.

• Check and remove manifests/03_service.yaml, it does not seem to be useful (at least now).

• Use DeploymentController from library-go to sync Deployments.

• Get rid of common/ package? It does not seem to be useful.

• Use StaticResourceController for static content, including the snapshot CRDs.

Note: if this refactoring introduces any new conditions, we must make sure that 4.11 snapshot controller clears them to support downgrade! This will need 4.11 BZ + z-stream update!

Similarly, if some conditions become obsolete / not managed by any controller, they must be cleared by 4.12 operator.

Exit criteria:

• The operator code is smaller.

• No regressions in standalone OCP.

• Upgrade/downgrade from/to standalone OCP 4.11 works.