DynamicTablesPkg: FdtHwInfoParser: CM Object descriptor helper

DynamicTablesPkg: FdtHwInfoParser: CM Object descriptor helper

FdtHwInfoParserLib is an instance of the HwInfoParser. The
FdtHwInfoParser parses a platform Device Tree and populates
the Platform Information repository with Configuration
Manager objects that describe the platform hardware.
These Configuration Manager objects are encapsulated in
Configuration Manager Object Descriptors.

Therefore, add helper functions to create and free the
Configuration Manager Object descriptors.

Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>