Allow hook for LiveDashboard historical data at client connection

Thanks! I see the tz_world discussion here Tz_world / timezone_boundary_builder update

I wonder if maybe should just have a second example that pulls/pushes history from/into Redis or Postgres or something as an alternative for where keeping this data in memory is a concern, but would also like to understand/cover José’s concerns about when to possibly not resend some events and/or when reflecting on tags or other metric metadata may impact the response, so anyone using those who can help me test out the implementation in real world condition, hope to hear from you!