BaseTools: Compile AML bytecode arrays into .obj file

BaseTools: Compile AML bytecode arrays into .obj file

The AmlToHex script and Posix/WindowsLike wrappers convert
an AML file to a .hex file, containing a C array storing
AML bytecode. This ".hex" file can then be included in a
C file, allowing to access the AML bytecode from this C
file.

The EDK2 build system doesn't allow to a depict dependency
orders between files of different languages. For instance,
in a module containing a ".c" file and a ".asl", the ".c"
file may or may not be built prior to the ".asl" file.
This prevents any inclusion of a generated ".hex" in a
".c" file since this later ".hex" file may or may not
have been created yet.

This patch modifies the AmlToC script to generate a C file
instead of a ".hex" file.
It also adds the generation of an intermediate ".amli" file
when compiling an ASL file, and adds a rule to convert this
".amli" to a C file.

This allows to generate a C file containing the AML bytecode
from an ASL file. This C file will then be handled by the EDK2
build system to generate an object file.
Thus, no file inclusion will be required anymore. The C file
requiring the AML bytecode as a C array, and the ASL file,
will be compiled independently. The C array must be defined
as an external symbol. The linker is resolving the
reference to the C array symbol.

To summarize, the flow goes as:
 -1. ASL file is compiled to AML;
 -2. AML file is copied to a ".amli" intermediate file;
 -3. EDK2 build system applies the rule relevant to ".amli"
     files. This is, calling the "AmlToC" script, generating
     a C file from the ".amli" file;
 -4. EDK2 build system applies the rule relevant to C files.
     This is creating an object file.
 -5. EDK2 build system links the object file containing the
     AML bytecode with the object file requiring it.

Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Suggested-by: Tomas Pilar <Tomas.Pilar@arm.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>