[CI] Connect 3rd party CI

Owned by Daniel Pono Takamori (Unlicensed)
Last updated: May 20, 2021 by Jessica Gonzalez
  1. File a ticket naming the service and project you'd like to connect
  2. Once RelEng has created the backend bits you should 
    1. Add log shipping to Nexus so all committers can see the logs from the service
  3. Verify the service can talk to both Gerrit and Jenkins