E2E test: add docs for setting up hook in e2e test
What does this MR do and why?
Adds instructions for locally executing qa/qa/specs/features/api/3_create/repository/tag_revision_trigger_prereceive_hook_spec.rb
by giving instructions on how to create a server hook.
Since creating the server hook is part of the environment build it is not included in the steps.
Edited by Jay McCure