install docs updated to jessie and stretch

[boyska]

look ma, no virtualenv!

This PR only changes docs, nothing else. Therefore to test it you need to run python build_sphinx and look at build/sphinx/html/index.html. More specifically, I have changed only the "sysadmin" section.

Also, it would be great if you could test the documented procedure itself!

[boyska]

rebased to include #266

[boyska]

Could someone please have a look at this PR?

[boyska]

this is wrong; it actually is libreant.service

[cocconat]

Can you explain why do I need to add stretch repo? As debian user I always had many troubles in using testing repo! maybe a standard user will not add testing, if you don't offer an explanation in the wiki. ;)
by the way it compiles and it's clear.

[boyska]

cocco->nat:

Can you explain why do I need to add stretch repo?

yes, python-dominate is the reason. You're also right about your
concerns adding stretch repo to a jessie. I'll a warning providing
additional explanation and providing a command to set the default
release to jessie, so that you won't find with everything upgraded.

[cocconat]

I installed in a Virtualenv, it works fine.
Maybe a lil explanation of what happen after installation should be offered.
something like:
Libreant has configuration file in /etc/libreant, use this folder for presets too, maybe you want to create a daemon in systemd like this:
(e qua la unit)

[boyska]

cocco->nat:

Maybe a lil explanation of what happen after installation should be offered.
something like:
Libreant has configuration file in /etc/libreant

actually it has not. for debian packaging I configured this explicitly,
but that's generally false.
The point is that I should include so many steps!

• Create a dedicated user
• Create configuration directory
• Create systemd unit (and what about non-systemd distros?)
• Provide a "suggested" libreant.conf
  Basically everything I do in the debian package should be rewritten
  here, explained, AND made portable to different systems. I think that it
  is way too much for an installation guide! If we want to support a
  specific additional distribution, we'd better create a package for it.
  Is there a realistic case in which the sysadmin:
• can't use a supported distro
• wants to install system-wide
• can't just look at the debian package and "steal" from it
  ?

See also how #227 is still open and there is no consensus on the
"default" paths

use this folder for presets too

Again, see #227 : there is no consensus on the canonical PRESET_PATHS,
and nothing about it is implemented in the debian package. This is also
related to #237: only one (and very minimal) preset is provided.