[refactor] replace upstream comms with msg layer

Replace the fragile upstream communications with the new messaging
layer, improving the stability and performance of this API.

NOTE: this breaks previous clients
NOTE: this patch is missing client tracking, to handle children signals.
2 jobs for messaging-layer in 54 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #13612
rapl
py.test

00:00:29

 
  Style
passed #13613
flake8

00:00:25