closes APM-16, APM-20
flag = none
also adds context id and user id
to request annotations for APM
configures host-level sampling
TEST PLAN:
* enable apm collection on datadog agent on single test cluster
* push consul config to same cluster for enabling apm sampling
* push consul config depressing host sampling rate to 5%
* delayed job telemetry should show up in ddog
* trace count from active clusters should drop by an order of magnitude
Change-Id: I94d97b299ed14403e8b141629740a1627310b259
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/230592
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Simon Williams <simon@instructure.com>
Reviewed-by: David Warkentin <dwarkentin@instructure.com>
QA-Review: Simon Williams <simon@instructure.com>
Product-Review: Ethan Vizitei <evizitei@instructure.com>