FW PR #2864 Added navigation item management

[kirsty-hames]

Close will need updating to support PR - adaptlearning/adapt_framework#2864

Avoid targeting nav items for render e.g. $el.insertAfter($('.js-nav-back-btn')) as this will render elements within the .nav__item containers used to control the navigation layout. With CGKineo navigation plugins we started targeting Drawer or Back button as a way of controlling the dom order but this will no longer be needed. Suggest generic $el.appendTo('.nav__inner') as per contrib plugins like languagePicker.

Nav plugins that aren't updated to support nav item management but are rendered into .nav__inner will just display last inside the nav bar.