[Enhancement] Swappable Packages (#216)

Co-authored-by: Tim Lorsbach <tim@lorsba.ch>
Reviewed-on: enviPath/enviPy#216
Reviewed-by: liambrydon <lbry121@aucklanduni.ac.nz>
Reviewed-by: Tobias O <tobias.olenyi@envipath.com>

epdb/management/commands/load_enviformer.py

@@ -8,7 +8,9 @@ from django.conf import settings as s
 from django.core.management.base import BaseCommand
 from django.db import transaction
 
-from epdb.models import EnviFormer, Package
+from epdb.models import EnviFormer
+
+Package = s.GET_PACKAGE_MODEL()
 
 
 class Command(BaseCommand):