[Feature] how to display vela application yaml from CLI?

[wonderflow]

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

In #4230, when we need to get the application yaml, we have no way but using kubectl.

Describe the solution you'd like

I think we can have a command such as:

vela status <myapp> -o yaml

This can display the whole application with status.

Describe alternatives you've considered

Additional context

[Somefive]

Is it just an alternative for kubectl get app <myapp> -n <ns>? Or more functions like pretty format / coloring / subcommand would be supported?

[wonderflow]

Just an alternative is fine.

[StevenLeiZhang]

Here is already one flag named "detail-format"

➜  ~ vela -n vela-system status -h          
Show status of vela application.

Usage:
  vela status APP_NAME [flags]

Examples:
vela status APP_NAME

Flags:
  -c, --component string       filter service endpoints by component name
  -d, --detail                 display the realtime details of application resources
      --detail-format string   the format for displaying details. Can be one of inline (default), wide, list, table, raw. (default "inline")

So we could just reuse it

vela -n xxxx status  xxxx --detail-format yaml

[charlie0129]

/assign