ego token in cookie session

[leoraba]

Issue:

Currently ego token is stored in browser's local storage which may be vulnerable as is readable by any Javascript code that runs on the site.

Solution:

• Store ego token as session cookie, which is readably only by the server.
• Make use of next-auth library

[leoraba]

PR: https://github.com/overture-stack/dms-ui/pull/187