[Umbrella Issue] CLI usability improvements

[yue9944882]

• Comprehensive clusteradm get .. command:

  • get clusters:
    • Cluster get cmd #124
  • get addons:
    • Feat: clusteradm get addon command for list enabled addon #103
    • Feat: Get addon in a tree view #129
    • Show certificate expiry status:
      • API changes: Addon certificate tracking and more addon status condition types api#140
  • get works:
    • Add get work command #131
    • show feedback values
  • get hub-info:
    • Feat: clusteradm get hub-info #128
  • get klusterlet-info:
  • get clustersets:
    • Cluster get cmd #124
  • get placements: feat: clusteradm get placements #163
  • general -o [*table|tree|yaml] printers

• Clusterset operatibility:

  • create: Clusterset create cmd #123
  • add cluster/bind namespace: clusterset sub command #126
  • remove cluster
  • unbind namespace

• Version mgmt / Upgrading: Use clusteradm to upgrade ocm #121

  • Bundle version - fixed issue#83 #119

• Proxy / tunneling: command to utilize cluster-proxy #88

  • proxy health: Feat: Clusteradm proxy health command #90
  • proxy tunnel: (creating tunnels for kubectl-access to the managed clusters)
    • create
    • connect
    • delete
  • proxy stats: (collecting stats such as in-use bandwidth, connection counts, etc.)
  • proxy bench: (test the estimated maximum bandwidth & latency thru the tunnels)

• Addon management:

  • enable/disable: Add command addon #101

• Miscs:

  • prompt warning if running join command against hub cluster
  • prompt warning if running "hub" oriented commands against managed cluster
  • unjoin cluster: (removing registered managed clusters from the hub neatly)

• Manifest work:

  • create from static yaml files: create work command #134

• Testing: (covering all the new sub-commands above w/ e2e tests)

[qiujian16]

maybe also add create/delete work command?