[Feature] Make Matomo Site ID configurable via .env (#183)

Co-authored-by: Tim Lorsbach <tim@lorsba.ch>
Reviewed-on: enviPath/enviPy#183

epdb/views.py

@@ -237,6 +237,7 @@ def get_base_context(request, for_user=None) -> Dict[str, Any]:
             "enabled_features": s.FLAGS,
             "debug": s.DEBUG,
             "external_databases": ExternalDatabase.get_databases(),
+            "site_id": s.MATOMO_SITE_ID,
         },
     }