EventShapes: cmake cleanup, enable flake8

cmake cleanup of Reconstruction/EventShapes packages. Also enable flake8 where relevant.

Reconstruction/EventShapes/EventShapeAthenaPool/CMakeLists.txt

-################################################################################
-# Package: EventShapeAthenaPool
-################################################################################
+# Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 
 # Declare the package name:
 atlas_subdir( EventShapeAthenaPool )
 
-# Declare the package's dependencies:
-atlas_depends_on_subdirs( PUBLIC
-                          Database/AthenaPOOL/AthenaPoolUtilities
-                          PRIVATE
-                          Database/AthenaPOOL/AthenaPoolCnvSvc
-                          Reconstruction/EventShapes/EventShapeEvent
-                          Reconstruction/EventShapes/EventShapeTPCnv )
-
 # Component(s) in the package:
 atlas_add_poolcnv_library( EventShapeAthenaPoolPoolCnv
                            src/*.cxx