Reduce cardinality of some of GitLab's Prometheus metrics and fix observed duration reporting.

What does this MR do?

Changes number of buckets in a few histogram metrics, in order to reduce cardinality of metrics. Fixes gitaly_controller_action_duration_seconds to actually report seconds and not miliseconds

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered

What are the relevant issue numbers?

Closes: https://gitlab.com/gitlab-org/gitlab-ce/issues/41045