[sensu/client/server] add flag to disable rabbitmq configuration

[arthurzenika]

and configure transport when pillar is used.

And enable configuration of redis sentinels.

[EvaSDK]

Overall looks good but I wonder if having one sls, let's say transport.sls configuring transport.json, for handling transport configuration wouldn't help in reducing all these if's.

[powellchristoph]

@EvaSDK that sounds like a great idea. This formula was written a while ago and sensu has made changes. I wonder if a small refactor is in order.

[arthurzenika]

@EvaSDK I agree transport could gain from being centralized. As long as redis (and sentinel) are options there, that's be great.