Quiet mode option

[xpqz]

When running Link 'unsupervised', e.g. when using LOAD=∘∘∘, it would be nice if there was a way to silence Link's diagnostic output:

Link Warning: ⎕SE.Link.Create: .NET or .NetCore not available - watch defaults to 'ns'
Linked: # → /src

Maybe we could have a

]link.create # /my/path/here --quiet

(although I prefer commands be quiet by default, and instead have a --verbose option).

This would be nice when running APL code in Docker, in GitHub actions etc, not to have Link 'pollute' the output.

[abrudz]

I'd say that the API functions should be quiet (error or return a status result instead). User commands can be noisy.