Include `::1 localhost` in /etc/hosts

[Treysis]

Hello everyone,

it seems like some releases ago the mapping of localhost to ::1 was
removed. Why was this done? Many other distros don't do this (Debian,
Arch, Gentoo, OpenWrt), many other operating systems neither (macOS,
Windows). Not having localhost to resolve to ::1 is getting problematic.

Will 22.04 by default again introduce mapping of ::1 to localhost? If
not, I want to suggest to change this in the future. It seems like this
has been the case before.

Cheers,

Trey