Add a command line version override for scalafix

[Gedochao]

Since the scalafix version does not seem to be overridable at runtime (yet?), could we just hardcode in the build the scalaVersions cli is published with to avoid fetching/scanning that and reducing a bit the complexity?

Originally posted by @bjaglin in https://github.com/VirtusLab/scala-cli/pull/2968/files#r1811457824

I think we could. I did that to make scalafix upgrades less painful.

Maybe it would be better to move this fetching logic into the build and put values from scalafix-properties into Constants.scalafixScala212 and etc. However, I would turn that into an issue

Originally posted by @dos65 in https://github.com/VirtusLab/scala-cli/pull/2968/files#r1831705112