WIP: Attempt to fix Docker mapnik issues

[luandro]

This PR contains work-in-progress changes to fix the mapnik issues in the Docker container. The main branch has been reverted to commit 826b6a3 which is known to work properly.

Changes in this PR:

1. Updated the settingsBuilder.ts file to run mapeo-settings-builder in the background without waiting for it to complete
2. Added polling for the output file to check when it's ready
3. Updated the Dockerfile to include the necessary dependencies for mapnik
4. Updated the test-docker.sh script to test both CI and production modes

These changes are still work-in-progress and need further testing.

---

Pull Request opened by Augment Code with guidance from the PR author