New/changed Wiki documentation

[Marc Muehlfeld]

Hello,

two more completely new HowTos (please proofread):

* 
https://wiki.samba.org/index.php/Flexible_Single-Master_Operations_%28FSMO%29_roles

* https://wiki.samba.org/index.php/Demote_a_Samba_DC
   As samba-tool can't demote a foreign DC, the only way
   to demote a lost DC is through Windows. But sadly
   this currently fails (Bug #10595). So you can
   only demote a DC, that is still accessable at the moment.


Also I replaced the /Samba page with the new table of content 
https://wiki.samba.org/index.php/User_Documentation. The nav bar entry 
is also replaced. A forwarder was set on /Samba to the new page.


Regards,
Marc