Create fleet workspace for clusters outside of `fleet-local` and `fleet-default` namespace

[Danil-Grigorev]

Fleet has expectations on fleetworkspace resource, which is required to cleanup fleet bundle for agent deployment.

This resource also acts as a workspace in UI, which allows to display cluster and resources outside of fleet-local and fleet-default namespace.

CAAPF should allow to create the resource automatically, and remove the permission after all CAPI clusters in this fleetworkspace are removed.

https://fleet.rancher.io/multi-user#isolated-workspaces-in-rancher

[Danil-Grigorev]

Unfortunately this can’t get into 0.10.0, moving it to 0.11.0

[Danil-Grigorev]

Changes introduced in #321 would allow users to manually create FleetWorkspace on demand from UI or API, thanks to introducing field.cattle.io/allow-fleetworkspace-creation-for-existing-namespace annotation on a namespace resource.

Ref: rancher/webhook#932