[FAB-2493] Refactor the golang platform driver

Clean up the code in prep for fixing FAB-2493.  No logic
changes are (intentionally) introduced.  We are merely
reorganizing the code for a few reasons:

1) The notion that we compute the hash is defunct.  This
   will be introduced at the codepackage level at a higher
   layer of abstraction.

2) There is code in the common layer that is GOLANG platform
   specific, so we scope this appropriately by moving it
   back into the platform driver.

There are other, similar optimizations that could be applied
to the JAVA platform.  However, this was not attempted in
this body of work.

Change-Id: I6febe38f40edfaba61f70256622cb400ec968840
Signed-off-by: Greg Haskins <gregory.haskins@gmail.com>