Added edxapp setting for AWS_S3_CUSTOM_DOMAIN
Added edxapp setting for AWS_S3_CUSTOM_DOMAIN

ECOM-4081

marcore/configuration,jorgeomarmh/configuration,armaan/edx-configuration,proversity-org/configuration,rue89-tech/configuration,nunpa/configuration,pobrejuanito/configuration,Stanford-Online/configuration,mitodl/configuration,armaan/edx-configuration,appsembler/configuration,marcore/configuration,gsehub/configuration,arbrandes/edx-configuration,gsehub/configuration,Stanford-Online/configuration,mitodl/configuration,proversity-org/configuration,proversity-org/configuration,hastexo/edx-configuration,hks-epod/configuration,arbrandes/edx-configuration,open-craft/configuration,gsehub/configuration,hastexo/edx-configuration,hks-epod/configuration,rue89-tech/configuration,hastexo/edx-configuration,arbrandes/edx-configuration,hastexo/edx-configuration,stvstnfrd/configuration,openfun/configuration,rue89-tech/configuration,arbrandes/edx-configuration,mitodl/configuration,hks-epod/configuration,EDUlib/configuration,Livit/Livit.Learn.EdX.configuration,gsehub/configuration,openfun/configuration,Stanford-Online/configuration,pobrejuanito/configuration,marcore/configuration,EDUlib/configuration,openfun/configuration,proversity-org/configuration,open-craft/configuration,jorgeomarmh/configuration,appsembler/configuration,stvstnfrd/configuration,Stanford-Online/configuration,stvstnfrd/configuration,open-craft/configuration,nunpa/configuration,edx/configuration,michaelsteiner19/open-edx-configuration,openfun/configuration,marcore/configuration,Livit/Livit.Learn.EdX.configuration,jorgeomarmh/configuration,edx/configuration,open-craft/configuration,mitodl/configuration,stvstnfrd/configuration,proversity-org/configuration,jorgeomarmh/configuration,nunpa/configuration,EDUlib/configuration,michaelsteiner19/open-edx-configuration,EDUlib/configuration,nunpa/configuration,pobrejuanito/configuration,armaan/edx-configuration,armaan/edx-configuration,rue89-tech/configuration,gsehub/configuration,hks-epod/configuration,EDUlib/configuration,appsembler/configuration,Livit/Livit.Learn.EdX.configuration,stvstnfrd/configuration,michaelsteiner19/open-edx-configuration,arbrandes/edx-configuration,rue89-tech/configuration,hastexo/edx-configuration,michaelsteiner19/open-edx-configuration,pobrejuanito/configuration,hks-epod/configuration,Livit/Livit.Learn.EdX.configuration,edx/configuration,edx/configuration,Stanford-Online/configuration,appsembler/configuration