Investigate consul sessions

[RaasAhsan]

When authentication is successful, we generate a token that is intended to be used to keep a session. We should look at consul's session API and see how to use it to implement node sessions on the master:

Requirements:

• We can create a session for a node after successfully authenticating
• We can delete a session after it disconnects
• We can expire the session after some interval
• We can reset the session expiry to refresh a session