Hmm so I got the module to work and I see how I can define a binary type for a field. However I don't think this would work. I can't do a form-data POST against some endpoint had have the file be saved into that targeted column.
I guess a better question would be, does Kentico have page that I can post to that would accept a form-data POST, and then would return some GUID of the uploaded file?
I looked at the media uploader web part, to see how it does a POST, and there is a ton of stuff in the request and probably very tight coupling
Edit: looks like I am limited to using base64 encoding and the rest api. Would be nice if whatever the media uploader control posts to, I can also post outside of the .net context.