Moving from_XYZ() functions in demograhpics module into Demographics class to properly support Demographics inheritance scheme

Author: ckirkman-IDM

emod_api/demographics/Demographics.py

@@ -10,7 +10,7 @@
     DemographicsGeneratorConcernChain,
 )
 from emod_api.demographics.Node import Node, nodeid_from_lat_lon
-from emod_api.demographics.Demographics import Demographics
+from emod_api.demographics.demographics import Demographics
 from emod_api.dtk_tools.support.General import init_logging
 
 logger = init_logging("DemographicsGenerator")