feature request: Symlink /etc/hosts to /etc/writable/hosts

Created by: kkeijzer

Description of the feature

/etc/hostname is symlinked to /etc/writable/hostname, and /etc/writable/ is in turn a bind mount to /userdata/system-data/etc/writable. This makes it possible to change the hostname without having to edit the system-image.

The localhost hostname however is also in /etc/hosts, which would then still be ubuntu-phablet, causing sudo to throw warnings if the local DNS server can't resolve the phone's new hostname.

Also, many people use uAdBlock, which currently requires remounting / as rw and concatenating the blacklist to /etc/hosts. This may be lost on some full system upgrades, channel switches, et cetera.

If /etc/hosts would effectively be /userdata/system-data/etc/writable/hosts, this would be a lot easier to manage.