Remove deprecated Prometheus metrics from the docs
Our documentation GitLab Prometheus metrics lists a number of metrics, but some of them are not available anymore. Few examples:
redis_ping_latency_seconds
db_ping_latency_seconds
filesystem_access_latency_seconds
- ...
We need to go through the list available in the docs, remove all obsolete metrics and add new ones if any.
Edited by Alexandr Tanayno