Separate directory for projects?

[marcverhagen]

Because

Now all project directories are at the top-level. This implies, and this is also reflected in the readme file, that all top-level directories in the repository are considered to be project directories (with the exception of the batches directory). There are some drawbacks to this:

• If we add a directory that is not a project directory then we need to document this
• Scripts that are looking for project directories have to rely on some heuristics like "is there a process.py file" or is there a "golds" directory, which are a bit fragile.
• Once we get a lot more projects then the top-level directory gets to be quite crowded and navigation will get harder.

If there are no major repercussions for existing scripts then I would like to add a "projects" directory.

Done when

No response

Additional context

No response