fix: remove jquery cache on destroy
js: rename 'setItem' to 'val'
js: use dedicated function to bind form events
js: rename 'itemIsEmpty' by 'isEmpty'
js: add form in a dedicated function
js: check if form is available before display/hide functions
js: add 'resetForm' function
js: add jsdoc
js: unbind form properly
js: improve jsdoc
js: add 'show'/'hide' functions
js: add 'onShown'/'onHidden' callbacks