feat(research): add research study management functionality

- Implemented models for ResearchStudy, ResearchStudyArm, and ResearchParticipant.
- Created views for listing, creating, updating, and exporting research studies.
- Added bulk participant generation feature with CSV and JSON support.
- Developed templates for study management, participant entry, and bulk generation.
- Introduced URL routing for research study operations.
- Added utility functions for randomisation and participant assignment.
- Implemented participant intake process with demographic data collection.
- Ensured proper handling of participant CIDs and assignment methods.

rad/urls.py

@@ -50,6 +50,7 @@ urlpatterns = [
     path("sbas/", include("sbas.urls"), name="sbas"),
     path("generic/", include("generic.urls"), name="generic"),
     path("atlas/", include("atlas.urls"), name="atlas"),
+    path("research/", include("research.urls"), name="research"),
     path("rcr/", include("rcr.urls"), name="rcr"),
     path("rota/", include("rota.urls"), name="rota"),
     path("oef/", include("oef.urls"), name="oef"),