feat: add ProviderType enum

This is used to give identities a type and to easily get the identity any auth method would need.

Signed-off-by: Philip Molares <philip.molares@udo.edu>

src/identity/provider-type.enum.ts

@@ -0,0 +1,18 @@
+/*
+ * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export enum ProviderType {
+  LOCAL = 'local',
+  LDAP = 'ldap',
+  SAML = 'saml',
+  OAUTH2 = 'oauth2',
+  GITLAB = 'gitlab',
+  GITHUB = 'github',
+  FACEBOOK = 'facebook',
+  TWITTER = 'twitter',
+  DROPBOX = 'dropbox',
+  GOOGLE = 'google',
+}