iNaturalist Spectrogram

Adds a toggleable spectrogram to iNaturalist audio observations. This was kinda roughly done and it's not super customizable in its current state but it works decently enough.

Long audio takes a long time to process (maybe as long as the audio is itself?)

Thanks to Jim Vallandingham for his work on spectrogram.js, which this is built off of: https://github.com/vlandham/spectrogramJS