Dev env and Github actions

[davidmh]

Since we're planning on modifying more than a few small things in this fork, we should:

• Enable local and CI environments using nix
• Plug the tests into a Github action

QA steps

Since you already have nix and direnv installed, all you need to install now is devenv as a standalone tool:

nix profile install nixpkgs#devenv

After that all you need to do is run direnv allow in the path for this project.

[sgoel]

Qa steps worked for me!

[sgoel]

@davidmh you mentioned in standup that this diff allows developers to not have to worry about the java dependencies on their system, but where is that defined? I don't see a JDK version being referenced anywhere

[davidmh]

Is set here:

OpenRailRouting/devenv.nix

Lines 4 to 5 in 166d3f9

	languages.java.enable = true;
	languages.java.maven.enable = true;

Since we're not specifying a jdk version, it goes with the default for the current release of devenv:

https://github.com/cachix/devenv/blob/main/src/modules/languages/java.nix#L17-L26

It installs java 21.0.2:

Do we need a specific version?