Make logos available under /logos

[Kobzol]

I noticed on my GitHub page that the Rust logo stopped working. I was using a link to https://www.rust-lang.org/logos/rust-logo-16x16-blk.png, but that is now uder https://www.rust-lang.org/static/logos/rust-logo-16x16-blk.png.

This PR makes the logos available also under the original URL. Note that we can't use HTML redirects here, as it's a static file asset (an image).

[senekor]

Why exactly do we need this? What is "your GitHub page" and can you update the link there?

[Kobzol]

I just meant this, I used an image there that pointed to https://www.rust-lang.org/logos/rust-logo-16x16-blk.png.

The motivation for this PR is to simply keep backwards compatibility of links to logos with the old website, before the move to a static web. I did a quick GitHub search, which shows that a lot of places use these links. But all these links now result in a 404 page, which seemed like a shame.