BaseTools/GenFds: cleanup GenFds

1) remove wildcard imports and use explicit imports
2) refactor to use shared variables from Common/DataType
3) rename to not shadow imports
4) don't assign a variable in a loop (just do final assignment)
5) remove spaces, parens, unused or commented out code, etc.
6) merge unnecessary parent classes into child
7) refactor to share DXE and PEI apriori GUIDs from one place
  this includes changes to Build and EOT files
8) for PEP8, dont use __ for custom methods.

Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Bob C Feng <bob.c.feng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jaben Carsey <jaben.carsey@intel.com>
Reviewed-by: Yonghong Zhu <yonghong.zhu@intel.com>

BaseTools/Source/Python/GenFds/Region.py

@@ -20,7 +20,6 @@ from struct import *
 from .GenFdsGlobalVariable import GenFdsGlobalVariable
 from io import BytesIO
 import string
-from CommonDataClass.FdfClass import RegionClassObject
 import Common.LongFilePathOs as os
 from stat import *
 from Common import EdkLogger
@@ -32,15 +31,20 @@ from Common.DataType import BINARY_FILE_TYPE_FV
 ## generate Region
 #
 #
-class Region(RegionClassObject):
+class Region(object):
 
     ## The constructor
     #
     #   @param  self        The object pointer
     #
     def __init__(self):
-        RegionClassObject.__init__(self)
-
+        self.Offset = None       # The begin position of the Region
+        self.Size = None         # The Size of the Region
+        self.PcdOffset = None
+        self.PcdSize = None
+        self.SetVarDict = {}
+        self.RegionType = None
+        self.RegionDataList = []
 
     ## PadBuffer()
     #