Refactor URL settings form (and others) to use the new $_settings method

Currently CRM_Admin_Form_Setting_Url uses a mix of the old method of (define setting fields in buildQuickForm), and the new method of just adding to the $_settings array and relaying on getFields to supply meta data (in parent class). We should convert older method to new and also audit other settings forms for similar issues.

Also, move require_cvv_backoffice setting to a new component preference form for CiviContribute since it doesn't really make sense to be included in Resource URL settings form.