Refactor gitaly recording rules
Refactor some gitaly gRPC recording rules to reduce evaluation time.
Split grpc_server_handling_seconds_bucket to separate group
- Set group interval to 1m to match rate1m.
- Add new per-instance handling bucket rule.
- Use pre-computed data for various summaries.
Split grpc_server_handling_seconds_bucket irate into separate group.
Split remaining grpc rules into misc group.
- Set group interval to 1m.
Signed-off-by: Ben Kochie bjk@gitlab.com