[-] BO: fixed lots of UI bugs in CMS:

- no more id_category (doesn't exists, it's id_cms_category)
- change category position now redirects in parent category (not at root category)
- change category status now redirects in parent category (not at root category)
- delete category now redirects in parent category (not at root category)
- add a new category now redirects in parent category (not at root category)
- delete multiple categories now redirects in parent category (not at root category)
- now execute parent::postProcess() only if none action found (duplicate postProcess was done)
- now redirects to CMS form if found errors (not at root category)
- fixed unexists $object variable (was $cms) for saveAndStay
- delete multiple cms content now redirects in parent category (not at root category)
- change cms content position now redirects in parent category (not at root category)
- change cms content status now redirects in parent category (not at root category)