LBaaS TLS termination capability specification

This document comes to specify TLS termination
capabilities of LBaaS.
The document defines the scope of the first release,
covers configuration options, external requirements,
data model modifications, functional specification,
testing requirements, etc.

Change-Id: I322724946104b836b9a1589c183945496a5e7aff
Implements: blueprint lbaas-ssl-termination
Merge "LBaaS TLS termination capability specification"