Redis-based matchmaker

Introduces a reference implementation
of a matchmaker (based on redis) that
supports dynamic host/topic registrations,
host expiration, and hooks for consuming
applications to acknowledge or neg-acknowledge
topic.host service availability.

Implements blueprint advanced-matchmaking

Change-Id: I8608d2089fca118b0e369f2eb5c6aedacf6821fe
Merge "Redis-based matchmaker"