Add bundler support to dream2nix

We should try to use `dream2nix` as we expand support to other runtimes. For this to work in Ruby apps, dream2nix needs bundler support added. We can take inspiration from the NodeJS [translators](https://github.com/nix-community/dream2nix/tree/main/src/translators/nodejs) and [builders](https://github.com/nix-community/dream2nix/tree/main/src/builders).

We can wrap [https://github.com/nix-community/bundix] to start, or attempt to build a pure implementation in Nix.

Start by reading dream2nix's src/translators/nodejs and src/builders, then compare the available Bundix wrapper approach with a pure implementation. The work is done when Ruby applications can use dream2nix with Bundler support; the issue does not identify specific tests or files in nix-base.

Written by the indexing model from the issue text.