feat: implement SCIM handler for SCIM 2.0 compliance (#25572)

Rewrites the SCIM 2.0 user provisioning handler to be RFC 7644
compliant. Verified against an external IdP Okta.

Behavior is OPT IN

coderd/database/modelqueries.go

@@ -413,6 +413,8 @@ func (q *sqlQuerier) GetAuthorizedUsers(ctx context.Context, arg GetUsersParams,
 		arg.AfterID,
 		arg.Search,
 		arg.Name,
+		arg.ExactUsername,
+		arg.ExactEmail,
 		pq.Array(arg.Status),
 		pq.Array(arg.RbacRole),
 		arg.LastSeenBefore,