aarch64 (arm64) package installation support

[ixty]

Hello, you can use the following line to add support for arm64 packages:
"aarch64": "wget -O - http://bin.entware.net/aarch64-k3.10/installer/generic.sh | /bin/sh"

Thanks for this very useful project!

[nongiach]

Hey, perfect, love it. I still need to get ride of this HTTP cleartext issue ^^. Do you mind doing a pull request ? I will gladly do it for you but I'd like to boost PR stats :D

[ixty]

Yeah ok sure, I'll do that sometime this weekend.
As for https, bin.entware.net does support it so the installer URL can be set to use it but i have no ideas about opkg internals and if packages can be downloaded securely.

[nongiach]

Hmm, I will predownload all .sh scripts and put them on this github. At some point if I have enough motivation I will repackage everything to compress all images to 15mo and preconfigure them.