PluginDescriptor contract needs to be properly defined and documented

[anujc25]

Describe the feature request

Currently as part of plugin-runtime library, PluginDescriptor is defined as an API contract between Core CLI and plugin developers to provide plugin specific details. Ref: https://github.com/vmware-tanzu/tanzu-framework/blob/main/cli/runtime/apis/cli/v1alpha1/catalog_types.go#L101-L159

However, this PluginDescriptor currently contains things that Plugin Authors cannot and should not configure and those additional details are being used by core CLI to do some additional post processing. This additional fields like InstallationPath, Discovery, Scope, Status and DiscoveredRecommendedVersion doesn't make sense to be part of PluginDescriptor.

As part of this issue, we need to solve the problem of this additional fields in the PluginDescriptor by removing from PluginDescriptor and moving it to implementation details on how Tanzu CLI manages the plugin.

Also, Responsibility of PluginDescriptor needs to be defined properly.

Describe alternative(s) you've considered
None

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

• ( ) APIs
• ( ) Addons
• (x) CLI
• ( ) Docs
• ( ) IAM
• ( ) Installation
• ( ) Plugin
• ( ) Security
• ( ) Test and Release
• ( ) User Experience
• ( ) Developer Experience

Additional context