allow passing `project` to the `processes`, `nodes` endpoints

[superstar54]

Currently, when fetching the processes and nodes endpoints, it projects everything, which is too big and not necessary. It would be good that these endpoints accept project as an input.

[edan-bainglass]

At the moment, this is tricky, as we validate the response against the model, which may have required fields not overlapping with the user's projections. Alternatively, a general-purpose query builder endpoint returning an unvalidated response could serve any projection.

[edan-bainglass]

Query builder endpoint implemented in #98. Feel free to project there 🙂 As for projections on the get_many endpoints, TBD. As I mentioned, their results are validated against models. Projection would complicate this. But maybe we can find a clean way to address this. Anyhow, for now, POST to /querybuilder 🙏