BaseTools: Clean up not used code in BuildClassObject
    
    V2: Add back "from Common.DataType import *"
    
    1. Remove some import statement that are not used.
    2. Remove the Type value in the LibraryClassObject because we don't
    actually use it.
    
    Cc: Liming Gao <liming.gao@intel.com>
    Cc: Jaben Carsey <jaben.carsey@intel.com>
    Contributed-under: TianoCore Contribution Agreement 1.1
    Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
    Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>