First public release

First public release of websocket balancer.

• Stateful websocket balancer functionality implemented.
• Backend failures are handled with exponential back-off circuit breaker implementation.
• Runtime observability metrics exposed over prometheus.
• Remote administration of sessions, backends and frontend exposed over REST APIs. Designed for full DevOps automation.
• Backends can identify when it's a new connection versus when it is a reconnect initiated by balancer.