Include a flag for machine-readable output as a part of the management-cluster command

[zjs]

Describe the feature request

The TCE getting started guide has the user run tanzu management-cluster get to print a bunch of information about the management cluster, and then copy & paste the management cluster name.

It'd be nice if the management-cluster plugin provided a flag for JSON output (like other plugins do) so that the user could do something a like export MGMT_CLUSTER_NAME=$(tanzu management-cluster get -o jsonpath={…}).

Describe alternatives you've considered

None — and there may be better ways to solve this!

Affected product area (please put an X in all that apply)

• APIs
• Addons
• CLI
• Docs
• Installation
• Plugin
• Security
• Test and Release
• User Experience

Additional context

[stmcginnis]

This is partially addressed with using https://github.com/vmware-tanzu/tanzu-framework/blob/3ff281803db15a87a950be07b949351817bf26d7/pkg/v1/cli/component/output.go, but we need to restructure the current output. Right now it is a mix, so even when specifying a yaml or json format, there are parts of the output emitted that would need to be parsed out.