Enable running basics with no network connection out of the box

[Gedochao]

Is your feature request related to a problem? Please describe. Freshly after installing scala-cli it is necessary to have the internet connection after the installation, to download Scala, Java, Bloop etc. I would expect for that step to be skippable/handled during the installation process.

Describe the solution you'd like Scala CLI should be able to compile and run basic Scala code (no external dependencies whatsoever) with the default Scala version out of the box, no Internet connection required. (without pre-filling the coursier cache) Optimally Scala CLI should be able to detect if it has acces to the Internet on its own, but explicitly passing --offline is acceptable. Shipping scala-cli together with the default Scala (or possibly even Bloop) should be expected. It is okay for more advanced features to not work out of the box, this is about the minimal functionality.

Additional context Depends on #1421