Add to popular package managers

Presently, swiftly is not available on most system package managers. To ease its adoption, we should add it to Debian, Fedora, ... It should, in my opinion, also be included in the swift docker image on docker hub.

Overview: https://pkgs.org/search/?q=swiftly

https://news.ycombinator.com/item?id=39771053 Rustup is available in Ubuntu and Debian.