BaseTools: Decouple AutoGen Objects

BaseTools: Decouple AutoGen Objects

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1875

1. Separate the AutoGen.py into 3 small py files.
One is for AutoGen base class, one is for WorkspaceAutoGen class
and PlatformAutoGen class, and the one for ModuleAutoGen class.
2. Create a new class DataPipe to store the Platform scope settings.
Create a new class PlatformInfo to provide the same interface
as PlatformAutoGen. PlatformInfo class is initialized by
DataPipe instance.
Create a new class WorkspaceInfo to provide the same interface
as WorkspaceAutoGen. WorkspaceInfo class is initialized by
DataPipe instance.
3. Change ModuleAutoGen to depends on DataPipe, PlatformInfo and
WorkspaceInfo. Remove the dependency of ModuleAutoGen to PlatformAutoGen.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Steven Shi <steven.shi@intel.com>
Signed-off-by: Bob Feng <bob.c.feng@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Liming Gao <liming.gao@intel.com>