Use 'openshift-workspaces' as the suggested namespace for the all-namespaces installation mode

Currently, `openshift-operators` namespace is used as a suggested namespace for CRW installation in all-namespaces mode:

See https://files.slack.com/files-pri/T027F3GAJ-F02MLEVVBJR/image.png

With this setup it is not possible to have in-cluster monitoring checkbox enabled (checkbox will not appear for the existing namespaces). Details:

• https://bugzilla.redhat.com/show_bug.cgi?id=2023464

• https://github.com/openshift/console/pull/5529#discussion_r430419501 

In order to have the in cluster monitoring checkbox available we need to set the suggested namespace to `openshift-workspaces` as we already doing for the single-namepsace installation.

This issue is a prerequisite for https://issues.redhat.com/browse/CRW-2326