Add Project to case sets

[williamparry]

Add another layer above so that case sets are tied to projects. This will involve adding another table and foreign key to the case sets.

Projects can have:

• Title (e.g. My Research Project)
• Lead (e.g. William)
• Categories (optional, but can have several)
• (case sets that can be regenerated)

This way we can have multiple projects each with their own case sets.