process-compose: Add programs.process-compose module

[StijnRuts]

Description

Allow configuring settings.yaml, theme.yaml, and shortcuts.yaml for Process Compose

Checklist

• Change is backwards compatible.

• Code formatted with nix fmt or
  nix-shell -p treefmt nixfmt deadnix keep-sorted --run treefmt.

• Code tested through nix run .#tests -- test-all or
  nix-shell --pure tests -A run.all.

• Test cases updated/added. See example.

• Commit messages are formatted like

  {component}: {description}
  
  {long description}
  

  See CONTRIBUTING for more information and recent commit messages for examples.

• If this PR adds a new module

  • Added myself as module maintainer. See example.
  • Generate a news entry. See News
  • Basic tests added. See Tests

• If this PR adds an exciting new feature or contains a breaking change.

  • Generate a news entry. See News

[StijnRuts]

It's failing with attribute 'stijnruts' missing on meta.maintainers = [ lib.maintainers.stijnruts ];, but I added myself to modules/lib/maintainers.nix. Does anyone know what I did wrong?