Add end to end test that exercises hooks for Operations service package tests

Modifies the operations tests to go through hooks. This MR creates an easy way to spin up a mock gitlab server that the hooks can talk to in order to ensure that the correct values are getting passed all the way down to the hooks and into the gitlab server.

Note: this change will increase the time to run the test for the operations service by about 45s. This is due to the ruby hooks that get run with each RPC operation. While not ideal, this cost is reasonable in that it allows for better confidence that the hooks are getting hit correctly.

Once we transition the hooks off of ruby into go, this will improve significantly.