use field proxyType to override default proxy setting

mediametadatatodb_app/resources/MediametadataToDB.py

@@ -137,7 +137,10 @@ def _extract_dig_obj_vals(msg, access_status) -> dict:
             # route goes over the internal image server
             return_values['proto'] = 'redirect'
         else:
-            return_values['proto'] = 'proxydirect'
+            if msg['proxyType']:
+                return_values['proto'] = msg['proxyType']
+            else:
+                return_values['proto'] = 'proxydirect'
     else:
         return_values['proto'] = 'file'
         if return_values['type'] == 'image':