Added the 'core.tcp_info' command to the exporter

[karstenjakobsen]

The kamcmd core.tcp_info command will also retrieve some TLS connection stats. This is useful if you need information regarding TCP and TLS connections. Example:

{
	readers: 8
	max_connections: 4096
	max_tls_connections: 4096
	opened_connections: 595
	opened_tls_connections: 595
	write_queued_bytes: 0
}

[florentchauveau]

Hello @karstenjakobsen!

Thank you for this. I've merged the "tls.info" before, could you rebase and resubmit?

Best

[florentchauveau]

Also, if core.tcp_info is available without loading a specific module, it should be safe to add it as a default collector in main.go.

What do you think?

Don't forget to update the README.md, the section about default metrics, if you think we can enable it by default :)

[karstenjakobsen]

I have fixed conflicts and added core.tcp_info to main.go