User accounts

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.

.env.example

@@ -18,3 +18,11 @@ DATABASE_URL="postgresql://postgres:postgres@localhost:5432/openpipe?schema=publ
 OPENAI_API_KEY=""
 
 NEXT_PUBLIC_SOCKET_URL="http://localhost:3318"
+
+# Next Auth
+NEXTAUTH_SECRET="your_secret"
+NEXTAUTH_URL="http://localhost:3000"
+
+# Next Auth Github Provider
+GITHUB_CLIENT_ID="your_client_id"
+GITHUB_CLIENT_SECRET="your_secret"