[Feature request] Implement AES-IGE

[watzon]

Hi there! First of all, love your lib. Just started getting into Deno myself and it's nice to see a good crypto library already exists. I'm working on porting another very large project to Deno, and it requires the AES-IGE block cipher. IGE isn't used much at all except by Telegram for their MTProto protocol, but it would be really helpful to me to have it available in your library.