[Feature] Simple template extension mechanism (#361)

Co-authored-by: Tim Lorsbach <tim@lorsba.ch>
Reviewed-on: enviPath/enviPy#361

epdb/apps.py

@@ -16,6 +16,10 @@ class EPDBConfig(AppConfig):
         model_name = getattr(settings, "EPDB_PACKAGE_MODEL", "epdb.Package")
         logger.info(f"Using Package model: {model_name}")
 
+        from .autodiscovery import autodiscover
+
+        autodiscover()
+
         if settings.PLUGINS_ENABLED:
             from bridge.contracts import Property
             from utilities.plugin import discover_plugins