Create a way to get a structured representation of a given .NET CLI command

[baronfel]

Is your feature request related to a problem? Please describe.

It can be useful for tools that are doing feature-probing of the .NET CLI to provide some structured representation of the CLI Command being invoked.

Describe the solution you'd like

This structured representation should provide access to

• the names and aliases of the command (if any)
• the options on the command
• the arguments on the command
• the subcommands on this command (recursively)

In this output, hidden items should be shown.

Additional context

The least grammar impacting way to do this would be a Directive, a la dotnet run [structure format=json], but there's space for some kind of global flag that could be used as well (dotnet run --dump-grammar?).

This was first requested in dotnet/aspire#7112 (comment).