Add Borgun gateway

Is this the correct URL? Does Borgun use some kind of IP whitelisting in production?

```
https://www.ssllabs.com/ssltest/analyze.html?d=gateway01.borgun.is
No secure protocols supported
```
```
curl -vi -m 5 https://gateway01.borgun.is/ws/Heimir.pub.ws:Authorization
* About to connect() to gateway01.borgun.is port 443 (#0)
*   Trying 213.167.142.76... Timeout
* connect() timed out!
* Closing connection #0
curl: (28) connect() timed out!
```