RA-343: Include Process HL7 task

https://issues.openmrs.org/browse/RA-343

Added a method that adds Process HL7 task when module is started.
By the way, this would read more easily as:

    if (ProcessHL7InQueueTask.class.getName().equals(registeredTask.getTaskClass())

because a class.getName() is never going to be null, so you don't need to use StringUtils.equals.