Instrument git commands for tracing
This patch adds instrumentation for when gitaly shells out to git. That way we can know exactly how much time was spent shelling out, and to which command.
See:
Currently, long-running processes may be misattributed to the request that happened to start them. This was also noted in !2478 (merged). We may want to fix this by removing correlation id and parent span in that case, ensuring the process is not associated with an RPC.
refs https://gitlab.com/gitlab-com/gl-infra/infrastructure/-/issues/11679
Edited by Igor