LDEV-3275: Introduce SSO using Undertow mechanisms.
Valves do not exist in Undertow. Another approach had to be used.
In each WAR there is a file in META-INF/service dir which adds a class in request processing chaing.
For Central it is SsoProducer which put the authenticated account into shared session.
All other modules use SsoConsumer which takes the account and puts it into its security context.
In standalone.xml caching of credentials was switched off as it would prevent UniversalLoginModule from putting UserDTO into shared session.
TODO: use a simple pass-all authentication mechanism for static files like images and JS files.
