[feature] notifications system

[righel]

• users can watch events, objects and attributes and get notifications when:

  • event/obj/attr is updated
  • event/obj/attr has new correlations
  • event/obj/attr has a sighting
  • event/obj/attr has a proposal
  • attr is seen in a third-party system (SIEM, firewall logs for example)
  • event used for creating a case in flowintel-cm has been modified

• users can follow organizations and get notifications when:

  • new event from the org is synced/created

• notifications should be grouped so users don't get spammed (example 1 "Organization A created 100 events" notification instead of 100 notifications)

• mark all notifications as read