Connection Count Scale Test

[neonphog]

RESOLVES: #8

• Adds header config to the client so we can make use of the trusted ip setting in the server to get around rate limits for a bunch of local clients
• Writes a connection count scale test

I ran this locally and got to 20,000 connections before I got bored. This is way above the connection count issues we've been running into with the previous signal server / turn servers.

Stats { client_count: 20052, messages_sent: 2908654 }

Btw, each connection sends a message every 2 seconds, so we had almost 3 million messages sent by the time I killed it.

[ThetaSinner]

Yay for tests, and looks like good news in the results! :)