Add OpenID to CodiMD

With OpenID every OpenID capable provider can provide authentication for
users of a CodiMD instance. This means we have federated
authentication.

Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>

lib/config/default.js

@@ -145,5 +145,6 @@ module.exports = {
   email: true,
   allowEmailRegister: true,
   allowGravatar: true,
-  allowPDFExport: true
+  allowPDFExport: true,
+  openID: true
 }