Hittermtype2

[tomnelson]

Added HitTermType and changed hit list code to use it instead of Content for hit terms. The motivation for this was as follows:

• I saw that the document after the serialization and deserialization did not match the original for the HIT_TERM key/value. The existing code puts the accumulo key into the value of the HIT_TERM element, but that is lost during serialization/deserialization. This was evident while comparing to another effort to use json serialization. I felt that the use of Content may not have been a good choice, however changing to just use TypeAttribute with a StringType was a problem because it was difficult to differentiate between the hit term items and the actual query return items. I added a HitTermType that extends StringType. This class should probably live in datawave-type-utils in the future, when that project is ready for a release. At that time, the imports can be changed here to use that version.

[keith-ratcliffe]

@ivakegg , if you're ok with @tomnelson 's updates I think we can get this merged