feat(config): add config vars for default permissions for special groups

Co-authored-by: Tilman Vatteroth <git@tilmanvatteroth.de>
Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>
Signed-off-by: Philip Molares <philip.molares@udo.edu>

src/config/guest_access.enum.ts

@@ -0,0 +1,29 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export enum GuestAccess {
+  DENY = 'deny',
+  READ = 'read',
+  WRITE = 'write',
+  CREATE = 'create',
+}
+
+export function getGuestAccessOrdinal(
+  guestAccess: GuestAccess,
+): number {
+  switch (guestAccess) {
+    case GuestAccess.DENY:
+      return 0;
+    case GuestAccess.READ:
+      return 1;
+    case GuestAccess.WRITE:
+      return 2;
+    case GuestAccess.CREATE:
+      return 3;
+    default:
+      throw Error('Unknown permission');
+  }
+}