Documentation versioned
updated sysadmin guide for 1.11.2
release notes versioned apart and other stuff
Release notes generated from config informations

Other stuff fixed
added missed image
Different versioning strategy for release notes and documentation, and
other stuff.

- Added "About us" and "News sections"
- Fixed headers anchors
Fixed typos
Fixed releases' names to StoRM-v1.11.1 and StoRM-v1.11.2
Fixed typos in sysadmin guide (only latest)
Updated 1.11.2 release's rfcs and post
Added prerequisite on storage area permissions
release notes updated
Started writing StoRM Functional Description
added missed file from prev commit
work in progress on functional description
Added missed images
Site did not build on GitHub Pages for invalid UTF-8
Missing baseurl in config file
Wrong baseurl
updated release notes, posts, functional description, ready for
the 1.11.2 release