* Added some kestrel event counters
- Connection queue length - This is the amount of connections accepted and queued in the thread pool.
- Connection count - The number of connections
- Total connections - The total number of connections ever connected.
- Connection Rate - Connections per second
* Added TLS counters
- Current TLS handshakes
- Total TLS handshakes
- Failed TLS handshakes
- TLS handshake per second
* Added HTTP/2 queue length counter
* Improve the event information
- Add TLS version to handshake events
- Add HTTP version to request queue events
- Renamed HTTP/2 request queue length to http request queue
Contributes to #4769