InfoPanel: massive overhaul to support mobile size and PNG download

This patch reworks the mobile breakpoint to allow whitespace wrapping of
code snippets and does away with horizontal scroll. Overall, the
usability and intuitiveness is much better, though readability of the
code itself takes a hit.

In addition, we added the ability to download an icon as a PNG thanks to
the svg2png-converter library. PNGs adopt the current preview weight and
color, and are sized at 256x256.

package.json

@@ -31,6 +31,7 @@
     "react-scripts": "3.4.1",
     "react-use": "^15.3.2",
     "recoil": "^0.0.10",
+    "svg2png-converter": "^1.0.0",
     "tinycolor2": "^1.4.1"
   },
   "scripts": {