Support to multiple languages when create a c4builder project

[barbararochazup]

Maybe it should be helpful to support multiple languages.

I'm a committer in an OpenSource project, which has PT-BR and ENG doc versions. I aim to use c4 builder to document the project's architecture and integrate them with my doc. For this, I need to build two c4 builder projects, one in PT-BR and a second in English.
I think it should be an option when creating the project to allow support for multiple languages.

Something as:

• docs
  • pt-br
  • eng
  • fr
• src
  • pt-br
    • system.puml
    • system.md
  • eng
    • system.puml
    • system.md
  • fr
    • system.puml
    • system.md

If this sounds like a good idea, I'd be happy to also work on a PR for this.