Instagram embeds should support non-standard (non-square) sizes

[goldenapples]

Our shortcode for Instagram embeds has the crop ratio hard-coded to fit a square image. However, Instagram has supported non-square images for over a year now, and we should be able to support them.

Example of a landscape crop Instagram post:
https://www.instagram.com/p/BJcSHUTgAI0/?hl=en

Embed code:

<blockquote class="instagram-media" data-instgrm-version="7" style=" background:#FFF; border:0; border-radius:3px; box-shadow:0 0 1px 0 rgba(0,0,0,0.5),0 1px 10px 0 rgba(0,0,0,0.15); margin: 1px; max-width:658px; padding:0; width:99.375%; width:-webkit-calc(100% - 2px); width:calc(100% - 2px);"><div style="padding:8px;"> <div style=" background:#F8F8F8; line-height:0; margin-top:40px; padding:33.2407407407% 0; text-align:center; width:100%;"> <div style=" background:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACwAAAAsCAMAAAApWqozAAAABGdBTUEAALGPC/xhBQAAAAFzUkdCAK7OHOkAAAAMUExURczMzPf399fX1+bm5mzY9AMAAADiSURBVDjLvZXbEsMgCES5/P8/t9FuRVCRmU73JWlzosgSIIZURCjo/ad+EQJJB4Hv8BFt+IDpQoCx1wjOSBFhh2XssxEIYn3ulI/6MNReE07UIWJEv8UEOWDS88LY97kqyTliJKKtuYBbruAyVh5wOHiXmpi5we58Ek028czwyuQdLKPG1Bkb4NnM+VeAnfHqn1k4+GPT6uGQcvu2h2OVuIf/gWUFyy8OWEpdyZSa3aVCqpVoVvzZZ2VTnn2wU8qzVjDDetO90GSy9mVLqtgYSy231MxrY6I2gGqjrTY0L8fxCxfCBbhWrsYYAAAAAElFTkSuQmCC); display:block; height:44px; margin:0 auto -44px; position:relative; top:-22px; width:44px;"></div></div><p style=" color:#c9c8cd; font-family:Arial,sans-serif; font-size:14px; line-height:17px; margin-bottom:0; margin-top:8px; overflow:hidden; padding:8px 0 7px; text-align:center; text-overflow:ellipsis; white-space:nowrap;"><a href="https://www.instagram.com/p/BJcSHUTgAI0/" style=" color:#c9c8cd; font-family:Arial,sans-serif; font-size:14px; font-style:normal; font-weight:normal; line-height:17px; text-decoration:none;" target="_blank">A photo posted by 渡辺直美 (@watanabenaomi703)</a> on <time style=" font-family:Arial,sans-serif; font-size:14px; line-height:17px;" datetime="2016-08-23T06:55:49+00:00">Aug 22, 2016 at 11:55pm PDT</time></p></div></blockquote>
<script async defer src="//platform.instagram.com/en_US/embeds.js"></script>

This embed code reverses to [fusion-instagram url="https://www.instagram.com/p/BJcSHUTgAI0/"] , which renders like this:

I see that the image crop ratio is specified in the embed code markup by a padding value on the div wrapping the image: padding:33.2407407407% 0;. I think there should be a way to pull that value when reversing the embed code and convert it to a height parameter on the shortcode.