Remove redis/kryo stuff that is not used anymore
XD-2170: NoNodeException for job creation

When an admin process is elected leader/supervisor, it will query
the state of all streams and jobs. It does this by iterating all
streams under /xd/deployments/streams/[stream-name] and jobs under
/xd/deployments/jobs/[job-name]. Under each path, it is expecting a
modules node which contains all of the modules deployed for the stream or job.

The issue is that if *no* modules were deployed for the stream/job,
that node will not exist because it is created lazily by the container.
This is unlikely in the case of streams since a stream contains at
least two modules, but is much more likely with jobs since they
only contain one module.

The fix is to ensure that the
/xd/deployments/streams/[stream-name]/modules path (and the same for
jobs) is created upfront by the supervisor prior to creating the
module deployment requests. This will allow the supervisor to see
that no modules for the stream/job have been deployed and thus
take appropriate action.
XD-2119,XD-2143,XD-2144

* Add 'spring-boot-starter-security' as a dependency
* Set up the admininstration and management endpoints as insecure by default
* Unit tests for SSL
* Unit tests for security enablement

Disable AuditAutoConfiguration by default
XD-2147 Update Spring Boot to 1.1.7.RELEASE
XD-2145 - Shell changes:

* Use Apache HttpClient for authentication in the Shell
* admin config server' now supports the '--username' and '--password' parameters
* Supporting unit tests for HTTPS and authentication in the Shell.
Adding a null sink

- Null sink can be useful when the main stream isn't focused on
  stream destination but the tap streams are used for analytics etc.,
- It is also useful to iteratively add in steps to a stream
  without worrying about having to land data anywhere.
XD-2098: KafkaMessageBus
Fix remaining tests
Fix some warnings
Remove unneeded class
Externalize config