rook-operator-app release v2.0.0

Added

• PriorityClasses for osds/mons (#42).
• Subchart to manage the cluster resources (uses upstream chart) (#40).
• Make the Ceph version configurable from the main chart’s values (#40).
• Extended UPDATING.md to reflect the additional subchart (#40).

Changed

• Disable CephFS CSI driver by default (#43).