Adds no logo option

Added no logo optiuon to logo params and replaced the output of the
logo area with a position called logo if logo set to none.
Adds option to overridecore template.xml file
Revert "Adds no logo option"

This reverts commit 7a3462a96176cbefbc0fad00b780180eb1b877bc.
Removes Designed by Joomlart link in mod_footer override