Modified the api to PATCH the annotation position

Brute force style; I'm not very happy with the solution.
With jQuery, one can use it like this:

    $.ajax('/api/v1/page/Name/section/5/', {
        type: 'PATCH',
        contentType: 'application/json',
        dataType: 'json',
        data: JSON.stringify({attributes: attributes}),
        success: function (data) {
            console.log(data);
        },
    });