Missing animated icon for weather state

[OreoTheAvali]

Issue:
My weather source (the National Weather Service) issues weather with the state of "exceptional". Your waves.yaml references such an SVG but is actually missing the file it's referencing despite following the instructions to copy all the files in themes to /www/waves/ (except the waves.yaml).

My solution:
Copying the sunny.svg and renaming the copy exceptional.svg (since mine will likely always be about heat.)

Proposed solution: Create an SVG for "exceptional" weather events.