Domain session

[reshadi]

We need a mechanism to stitch together sessions that are part of one workflow, but may happen across various subdomains. The browser_session_id only works for apps on the same domain openned in the same tab.

assigning a session id to the top domain means that all tabs and apps on the same domain will get the same value. Instead, trying another approach in which a short lived cookie is set on the domain and then immediately picked up by the next application that is openned. In this way, we can stitch together flows between applications, and can continue to rely on ClientSessionID for 'per tab' session identification.