Parsoid debianization

First cut of a Parsoid Debian package.

- Package name parsoid
- Code in /usr/lib/parsoid, as it may depend on binaries in the future.
  Currently node_modules already contains binaries, although those are not
  actually used by Parsoid.
- system user parsoid, group parsoid
- logging to /var/log/parsoid/parsoid.log
- config in /etc/default/parsoid and /etc/parsoid/settings.js
- init script so that it works both in Ubuntu and Debian:
  sudo service parsoid restart
- Listen on port 8142 by default to avoid conflicts. Parsoid proper default
  will change from 8000 later.

To build without signing, in the top dir of the deploy repo:

dpkg-buildpackage -us -uc

Confirmed to install & start up fine on Debian unstable and Ubuntu precise
(ruthenium).

TODO:
- set localhost defaults to match those of the mediawiki package, and suggest
  that?
- Avoid the private copy of settings.js in the debian dir / clean up settings
  in general; ideally switch to json.

What I did:
- dh_make --native
- Edited debian/parsoid.install to install code and node_modules in
  /usr/lib/parsoid.
- Depend on node >=0.8.0 for now. Would really like >=0.10.24 here, but oh
  well.
- Set up an init file in parsoid.init. They will be picked up by
  dh_installinit. Add an output redirection hack for old start-stop-daemon on
  Ubuntu 12.04 LTS missing the --no-close option. Also makes sure that the log
  files are owned by parsoid:parsoid too.
- Create parsoid.postinst that creates the log dir and the user
- Add a parsoid.logrotate bit that will be installed by
  dh_installlogrotate

Bug: 53723
Change-Id: I21ff29d9cde0be9a651c210f31729832acc2750c