Allow upload types to render with an image instead of a magick render

[josefnpat]

I don't know what the code looks like now, but perhaps something like:

upload_types = {
  png => {mimetype=>'image/png', render=>'magick'},
  love => {mimetype=>'archive/zip', image=>'images/love.png'},
  lua => {mimetype=>'raw/text', image=>'images/lua.png', render=>'code:lua'},
}

reference:

[karai17]

A set of images for non-image file types would be handy. I am not currently looking at the file's mime type but I should start doing that for this specific case.

[karai17]

I updated the whitelist to have categories. I've added an audio thumbnail to the /static so that any filetypes listed under the audio category will pull that thumbnail.

I was going to add an archive category but @shakesoda convinced me otherwise. There are other places you can upload .loves or .zips such as mixtape.moe. Lapis-chan will remain media-focused for the foreseeable future.

Now that Lapis-chan depends on FFmpeg, it's not unreasonable to add video support, but I feel like it's kind of out of scope. For now, it's just images + webm, and audio.

If you have other category or filetype idea,s please open a new issue.