When a user attempts to adhere to the current documentation to use alternative
namespaces for both the operator and the cluster, they fail because
our common YAML file only has a single namespace for the cluster. This
change adds specific instructions to create operator namespace.
Closes: https://github.com/rook/rook/issues/13079
Signed-off-by: Redouane Kachach <rkachach@redhat.com>
(cherry picked from commit 745d6dc86f)