doc: remove much of the Italian translations
The Italian translation has not been updated since r31375 on
2008-01-27. Future commits were either mechanical or global.
- The committers guide still references CVS
- The handbook still references sysinstall
- Both still reference GNATS
In general the documentation is out of date sufficient and not being
updated.
The hard work of the previous contributors is much appreciated.
Leave the handbook as there is interest in continuing the project.