Update README in fuel-library repo

[Mike Scherbakov]

It needs complete rewrite as it doesn't reflect reality since it was closed-source project.
Please provide information:
a) general information on what is in this repo
b) Librarian and what is the connection with puppet-openstack
c) Enlist what are uniq puppet modules which can be reused by others, may be even besides openstack. For instance, l23network.
d) short explanation / reference to other guide how fuel-library is used within Fuel ecosystem.

[Stanislaw Bogatkin (sbogatkin)]

Lowered to 'Medium' accordingly to rules: https://wiki.openstack.org/wiki/Fuel/How_to_contribute#Confirm_and_triage_bugs

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/228602

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/228602
Committed: https://git.openstack.org/cgit/stackforge/fuel-library/commit/?id=06107883e56d766ef9551940b5c6ccd0c780222f
Submitter: Jenkins
Branch: master

commit 06107883e56d766ef9551940b5c6ccd0c780222f
Author: Alex Schultz <email address hidden>
Date: Mon Sep 28 15:01:14 2015 -0500

    Update README.md

    This change updates the README to include more useful information about
    fuel-library as an open source project.

    Change-Id: Ie31cc684307331cf3d51a56e3621101b1edd9505
    Closes-Bug: #1500069