Switch to systemd as pid 1
Originally created by Tails on #5821 (Redmine)
We’ve been wanting to supervise critical services (#5750 (closed)) for years, and e.g. systemd knows how to do that.
systemd is quite well integrated in Debian Wheezy, and has about a thousand reported users in Debian as of February 2012, while Wheezy is not out yet.
Moreover, Debian Jessie’s default init will be systemd.
So, we want to switch to systemd once Tails is based on Wheezy (#6015 (closed)).
Feature Branch: feature/jessie