[desktop] Building the HTML in 17.10

[Gunnar Hjalmarsson]

Hi!

The ubuntu-docs package has been converted to serve as a supplement to 
gnome-user-guide. To watch the current state of the 17.10 desktop guide 
locally, install both packages from artful and run:

yelp help:gnome-help

I have experimented with building the HTML from the installed files, and 
my impression is that doing so might be a reasonably convenient method 
going forward, after all.

Follow these steps to try out the method:

* Install ubuntu-docs from
   https://launchpad.net/~ubuntu-core-doc/+archive/ubuntu/ppa

* Install the artful version of gnome-user-guide from
   https://launchpad.net/ubuntu/+source/gnome-user-docs

(Note that you don't need to be on artful - the packages can be 
installed on e.g. 16.04 or 17.04.)

* Get an updated ubuntu-docs trunk branch

* cd to the html folder and run:
   make -f Makefile-from-installed (instead of just "make")
   make -f Makefile-from-installed install

Some keyboard-key-*.svg icons are missing, which has been reported in 
<https://bugs.debian.org/861869>.

-- 
Gunnar Hjalmarsson
https://launchpad.net/~gunnarhj