Added Redis Sentinel Support

[K-MTG]

Support for Redis Sentinel configuration as follows:

app.conf.broker_url = 'sentinel://:password@localhost:26379;sentinel://:password@localhost:26380;sentinel://:password@localhost:26381' app.conf.broker_transport_options = { 'master_name': "cluster1", sentinel_kwargs': {'password': 'password'} }

#34