- added EventCenter for receiving events from other modules
  and dispatching them to subscribers using server-sent events
- added events panel in UI, in dashboard page
- added entity links component in UI for presenting in UI entities
  link machine or app as an exposed box with link
- in Rakefile task serve_ui is changed: now it only builds UI,
  and UI is served by stork server over 8080 port and not using
  angular cli server by 4200 port (this is caused by not working
  SSE in angular cli proxy)
- added submitting events in several places