kubectl-gs release v2.3.0

Added

• Add description column to the get catalog limited to 80 characters.
• Add --enable-long-names feature flag to template cluster/networkpool/nodepool to allow resource names longer than 5 characters. Only for internal testing.
• Implement get clusters command for OpenStack.

Changed

• Add missing availability zones to cluster configuration for OpenStack.
• Change default catalog for cluster-* and default-apps-* apps from giantswarm to cluster.