Fix user management

Currently, application requires to be logged in (changes needed if anonymous mode is an option)

• Should fix looping redirection at login
• Add sign in / signup / forgot password forms if keycloak is disabled
• Add admin role management
• Add email validation

Email validation has been added, but email server can not be configured yet. Content of emails will appear in server logs in this version (email validation can also be disabled in settings)

index.js has been updated to show how admin role can be verified