Workspace PVCs are never updated and are not removed from the cluster

[amisevsk]

Description

The DevWorkspace PVC (claim-devworkspace) is not updated on reconcile cycles, so once it exists its configuration is static. In addition, it is not removed from a namespace when all DevWorkspaces are deleted and must be manually cleaned up.

[AObuchow]

PVC cleanup is closed by #834. Additional work regarding resizing the common PVC (i.e. modifying the PVC configuration) should be tracked in a new issue.