feat: Add initial AuthzQuerier implementation (#5919)

feat: Add initial AuthzQuerier implementation
- Adds package database/dbauthz that adds a database.Store implementation where each method goes through AuthZ checks
- Implements all database.Store methods on AuthzQuerier
- Updates and fixes unit tests where required
- Updates coderd initialization to use AuthzQuerier if codersdk.ExperimentAuthzQuerier is enabled

coderd/workspaces.go

@@ -371,6 +371,9 @@ func (api *API) postWorkspacesByOrganization(rw http.ResponseWriter, r *http.Req
 		return
 	}
 
+	// TODO: This should be a system call as the actor might not be able to
+	// read other workspaces. Ideally we check the error on create and look for
+	// a postgres conflict error.
 	workspace, err := api.Database.GetWorkspaceByOwnerIDAndName(ctx, database.GetWorkspaceByOwnerIDAndNameParams{
 		OwnerID: user.ID,
 		Name:    createWorkspace.Name,