feat: Add ability to enforce SSO

Closes #543, closes #545

server/api/controllers/show-config.js

@@ -10,6 +10,7 @@ module.exports = {
           response_mode: 'fragment',
         }),
         endSessionUrl: oidcClient.issuer.end_session_endpoint ? oidcClient.endSessionUrl({}) : null,
+        isEnforced: sails.config.custom.oidcEnforced,
       };
     }