DynamicTablesPkg: AML serialise interface

DynamicTablesPkg: AML serialise interface

AML Fixup and AML Codegen facilitate dynamic generation
of Definition Block tables. The AML byte stream that is
generated is represented in an AML tree. Once the AML
table generation is completed, the AML tree needs to be
serialised for installing as an ACPI table.

The AML serialise interface implements the functionality
to iterate the nodes in the AML tree, collating the AML
bytecode, computing the checksum and writing the AML byte
stream to a buffer that represents the Definition Block
table.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Co-authored-by: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Alexei Fedorov <Alexei.Fedorov@arm.com>