Handle dg-loader DGs approach with platform-logic

Handle dg-loader DGs approach with platform-logic

This commit takes care of adding the necessary code to be able to:
1) Convert JSON DGs to XML DGs in the dg-loader-dgs path
2) Load & Activate these converted XML DGs into the MySQL DB

This approach is used in appc.git's dg-loader-provider to handle DGs.
Combining platform-logic approach and dg-loader-provider approach to
handle DGs coming from these two separate paths.

Change-Id: I46505a3380afcdd3c6794e24fda75aef62ccc58f
Signed-off-by: Hector Anapan-Lavalle <ha076r@att.com>
Issue-Id:[APPC-287]