New split lib workflow

We need to:
- [ ] check that meta-analysis is still working
- [ ] finish preprocessing (split libs) connect per prep template
- [ ] make preprocessing async
- [ ] be able to connect to other studies raw data
- [ ] fix metadata summary per prep template
- [ ] add EBI submission
can a call to `_check_access` be made to assure that the user can access the study? The reason is that there are `delete` calls below which are currently trusted calls.