shrine

Pull request #1456: Feature/SHRINE2020 1504

Merge in SHRINE/shrine from feature/SHRINE2020-1504 to develop

* commit '058e28d0ad845e850d268b0f2a1ad896ce12acb2':
  Comments for reference.conf and shrine.conf for SHRINE2020-1504
  When to fix a todo as a comment on SHRINE2020-1504
  Configure the delay between sending node system updates SHRINE2020-1504
  Check that a node spec is substantially different from the stored one for SHRINE2020-1504
  Got messages flowing for SHRINE2020-1504
  Added sending node system spec updates for SHRINE2020-1504
  Database work to receive NodeSystemSpec for SHRINE2020-1504
  Missed a rename in SHRINE2020-1503, got it in SHRINE2020-1504
  Planning for SHRINE2020-1504