Remove live validation and default field okay message from administration

The live validation is not taken into account since a regression due to XWIKI-16623 and it has been voted to remove it in https://forum.xwiki.org/t/remove-the-live-validation-configuration-from-administration-registration/13325/

The default field okay message is not taken into account since the same regression and it has been voted to remove it in https://forum.xwiki.org/t/remove-the-default-field-okay-message-configuration-from-administration-registration/13331