Remove Scrimage classloader hack

[sloshy]

As described here: sksamuel/scrimage#217

And mentioned here: #529

There's a hack in MicrositeHelper.scala def createFavicons for changing out the current ClassLoader for the duration of using the Scrimage library. In Scrimage 4.1.0, after the above issue is fixed, there may be a way to pass in a classloader of your own, so we will still need to get a new classloader but we will be able to pass it through to the library instead of swapping it on the current thread.