Add "exceptional" weather icon

[rileytb]

For reference I am using Accuweather in Home Assistant and the https://github.com/pkissling/clock-weather-card integration which uses the icons from this repo to represent the weather.

However, when Accuweather shows the daily forecast as "exceptional" you can see here that it uses a circle with an exclamation point inside:

The maintainer for the clock-weather-card widget has been using the hurricane/vortex icon as they were not able to find a suitable substitute for "exceptional" weather. (a related issue)

I know that this might not be directly weather related, but could we get some sort of "exceptional weather" icon added for these scenarios?

[tykeal]

Duplicate of #21

[rileytb]

Oh nuts, I looked for something similar but apparently I missed that. Sorry!