Put CI URLs in ReleasingTor.md

arma asked us where the CI builders are.

The list is in ReleasingTor.md and on the wiki, but only the wiki has the URLs: https://trac.torproject.org/projects/tor/wiki/org/teams/NetworkTeam/CIFailures#CIBuilders

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information