Blueprint for Websockify security proxy framework

This blueprint proposes a generic framework for supporting
man-in-the-middle authentication and encryption between
Websockify and the hypervisor graphics servers.  It also
proposes a reference driver for that framework for TLS
security.

Spec for blueprint websocket-proxy-to-host-security

Change-Id: I45e759896e78889800ad7f8cbcb423dea02d5ea0
Merge "Blueprint for Websockify security proxy framework"