DynamicTablesPkg: AML Codegen

DynamicTablesPkg: AML Codegen

AML Codegen is a Dynamic AML technique that facilitates
generation of small segments of AML code. The AML code
generated using AML Codegen is represented as nodes in
the AML Tree.

Some examples where AML Codegen can be used are:
 - AML Codegen APIs can be used to generate a simple
   AML tree.
 - An AML template can be parsed to create an AML
   tree. This AML Tree can be searched to locate a
   node that needs updating. The AML Codegen APIs
   can be used to attach new AML nodes.
 - A combination of AML Fixup and AML Codegen can
   be used to generate an AML tree.

   The AML tree can then be serialised as a Definition
   Block table.

Following AML Codegen APIs are implemented:
 - AmlCodeGenDefinitionBlock()
 - AmlCodeGenScope()
 - AmlCodeGenNameString()
 - AmlCodeGenNameInteger()
 - AmlCodeGenDevice()

These AML Codegen APIs in combination with AML Resource
Data Codegen APIs can be used to generate a simple AML
tree.

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