tls: add histogram measuring ssl negotiation latency

[jmarantz]

Title: https://www.envoyproxy.io/docs/envoy/latest/configuration/listeners/stats#tls-statistics has no latency histograms, and they would be helpful for debugging connection latency issues.

I'd like to hear if, when addressing this bug, there are a few other counters/histograms we should add.

[kyessenov]

This issue probably subsumes https://github.com/envoyproxy/envoy/issues/33608

[github-actions[bot]]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or "no stalebot" or other activity occurs. Thank you for your contributions.

[github-actions[bot]]

This issue has been automatically closed because it has not had activity in the last 37 days. If this issue is still valid, please ping a maintainer and ask them to label it as "help wanted" or "no stalebot". Thank you for your contributions.