Remove dead Ruby code and unused binaries
Shell v10.1.0 never runs the Ruby code any more, so it can be safely removed in-general. However, in !338 (closed) I identified a number of test gaps that prevent us from removing all the specs and the Ruby environment right now.
Since we need to keep Ruby around for the build and install-time phases anyway, it's pragmatic to remove the definitely dead code now and punt that rewrite to a follow-up issue.
Most impactful of these changes is removing cmd/gitaly-*
. These three helper binaries make up 45MiB unpacked size, and are completely unused now.
Part of #173 (closed)