Migrate image urls off of Imgur to permanent hosting

[msprijatelj]

Imgur has recently indicated they would be purging old images not tied to an account as of May 15th. While I am unsure if Dustgrave's images are at-risk, I think it may be better safe than sorry to consider migrating the images to a hosting site under Massif Press's control, whether that's in an AWS S3 bucket, a Cloudfront host, or some other hosting site.

Potential at-risk images include the Talent icons and Frame images.

[msprijatelj]

With a recent update, this has been implemented for frames.json. Still concerned about the Talent icons, though, and hoping we can incorporate the original SVGs into compcon itself like we did with the Long Rim icons.