Allows for the creation of user accounts. A few notes on the specifics:
- Experiments are the main access control objects. If you can view an experiment, you can view all its prompts/scenarios/evals. If you can edit it, you can edit or delete all of those as well.
- Experiments are owned by Organizations in the database. Organizations can have multiple members and members can have roles of ADMIN, MEMBER or VIEWER.
- Organizations can either be "personal" or general. Each user has a "personal" organization created as soon as they try to create an experiment. There's currently no UI support for creating general orgs or adding users to them; they're just in the database to future-proof all the ACL logic.
- You can require that a user is signed-in to see a route using the `protectedProcedure` helper. When you use `protectedProcedure`, you also have to call `ctx.markAccessControlRun()` (or delegate to a function that does it for you; see accessControl.ts). This is to remind us to actually check for access control when we define a new endpoint.
