Rename _get_X_script functions to get_X_info

Functions that retrieve info usually have the word _get_ in them, I like to name mine MODULENAME_get_THINGITGETS so I'd like to rename structured_data_add_site_name_script to structured_data_get_site_name_info and structured_data_add_site_logo_script to structured_data_get_site_logo_info. In this case the adding is actually done after the getting, so I think the get name is also more appropriate.