Move the tool to summarize a failed pipeline to a generic .marge/hooks
directory. This will allow the fdo-bots repo to handle all marge hooks in
a consistent way across repositories that use this service.
Add a symlink to the bin/ci directory so that the pipeline summary tool
can still be run locally as well.
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32413>