Models: Remove deprecated arguments in constructors

[Andrey Sheshukov]

Change the way the models are initialized.

• Remove all @legacy_filename_initialization decorators in models/ccsn.py
• Remove all deprecated input parameters
  Remove workarounds for OConnor_2013 model:
• Remove class OConnor_2013
• Rename class _OConnor_2013_new to OConnor_2013
• Remove lines with workaround for ModelsTable and documentation:
  

  snewpy/python/snewpy/models/ccsn.py

  Lines 245 to 248 in db4cc20

   OConnor_2013.__init__.__doc__=dedent(OConnor_2013.__init__.__doc__)+_OConnor_2013_new.__init__.__doc__ 
   #make sure that only the latest class is present in the models table 
   all_models.remove(OConnor_2013.__mro__[1]) 
   all_models.add(OConnor_2013)