[RFC] request for the std.crypto.cypher.aes module

[Dejan Lekic]

I do not know if new module(s) in Phobos require DIP or not. I 
always thought DIPs are for language changes, not for library 
changes...

Anyway, I would like to request to add a new package to Phobos 
called `std.crypto.cyphers` and add the `aes` module there with 
implementations of AES-128, AES-192 and AES-256, with GCM variant 
too.

Yes, I am aware that we have more than 10 packages in dub 
repository that contain AES, but I believe Phobos should have own 
implementation of this standard cypher.