Add global config for `--offline`

[Gedochao]

Discussed in https://github.com/VirtusLab/scala-cli/discussions/3023

^{Originally posted by halloleo July 12, 2024} I need to run scala-cli as

scala-cli --power --offline

because my machine is not on the internet.

The option --power I can add with

$ scala-cli config power true

as a default option which is great.

I tried the same for --offline:

$ scala-cli config offline true

but here I get "Error: unrecognized key offline".

How can I add --offline to the default config?

Also, is there a way to suppress the informational output:

The --offline option is experimental Please bear in mind that non-ideal user experience should be expected. If you encounter any bugs or have feedback to share, make sure to reach out to the maintenance team at https://github.com/VirtusLab/scala-cli