Connection error to Virgo

Going to the new model page and entering a URL gave a red message:
```
HTTPConnectionPool(host='scidash-virgo', port=8080): Max retries exceeded with url: /org.geppetto.frontend/geppetto (Caused by NewConnectionError(': Failed to establish a new connection: [Errno 111] Connection refused',))
```
This was using the staging IP address on Slack: https://asuiconlab.slack.com/archives/CL7JKNG10/p1587728784005000.

Start at the new model page and reproduce the URL submission using the staging IP address linked in the issue. Trace how the page connects to scidash-virgo on port 8080 and inspect the reported connection-refused error. Done means the page can submit the URL without displaying this connection error, with the relevant staging connection path verified.

Written by the indexing model from the issue text.