REPL: add support for `//> using repository` directive / `:repository` command

[Gedochao]

What is this about?

Add support for //> using repository <address> directive in the REPL, and a corresponding :repository command.
This adds repositories to dependency resolution for coursier under the hood of //> using dep/:dep and similar commands/directives.

Details

• aliases like central, ivy2Local and m2Local should be supported, as per what Scala CLI / coursier support

Relevant docs

• relevant doc: https://scala-cli.virtuslab.org/docs/guides/introduction/dependencies#repositories
• Scala CLI directive reference: https://scala-cli.virtuslab.org/docs/reference/directives/#repository
• https://github.com/VirtusLab/scala-cli/blob/dff5037a3622e42774f7bebe8ea809d59047dc8d/modules/directives/src/main/scala/scala/build/preprocessing/directives/Repository.scala#L22