XD-1672 filepollhdfs Acceptance Test

* Hdfs based tests will use assertValidHdfs
* Remove overloaded SimpleFileSink.toDSL method
* Replaced FileSourceTest's triggers with http
XD-1747: Module deployment order is not guaranteed

Modified writeDeployment to deploy each module serially (but still
write out deployment requests for a module to multiple containers
at once). This is required to guarantee that modules for a stream
are deployed in the correct order.
XD-1520 Update ModuleOptions stream name defaults

- Fix Module options that use stream name as the default value
  - Add ${xd.stream.name} as the default value in appropriate
module options POJO and module options properties
  - This will allow `module info` command to display the default values
with ${xd.stream.name} wherever stream name is used

Following modules are fixed:
File Sink
Gemfire sinks
Aggregator
File source
Metrics
HDFS dataset
Hdfs + move into own dir
Post
Tail
JMS
SimpleFileSink uses StringUtils.hasText to check for null and empty strings for the fileName and directory when creating DSL string.