Req: Support file location redirects

[ghost]

So for people hosting their minecraft server at home, with a cable modem, have extremely limited upload speeds. So a 250mb modpack would saturate your link for about 30minutes when a client is downloading it. It would be nice for the server to first the tell client where the files are found before trying to download them (ie: an HTTPS location on AWS S3 for example; or the default, myself over 25565).