Release-notes for cs4.4: started (take #2)

Getting ready for cs4.4

* split about.rst into multiple file
* remove [tag] from initial proposal
* new features are 4.4
* new api are 4.4
* supported matrix is 4.4
* global.rst included in multiple page
* sysvm templates download url from jenkins until official urls.

Still remaining:

* complete new features
* upgrade instruction and valide the procedure
* complete new API

This patch should not contain a previous commit that was problematic. A Rebase into the branch pdion-pre4.4 as been performed.