[FIX] web: autofocus in autocomplete popup on a m2x field

* When the autocomplete popup list appears, the focus should be on first element in list, in order to quick create a new record if no match
* Tour.js has been modified because jquery ui autocomplete needs a mouseenter event to be notified that this element will be set

addons/web/static/src/js/tour.js

@@ -699,6 +699,7 @@ var Tour = {
                 click_event("mouseover");
                 click_event("mousedown");
                 click_event("mouseup");
+                $element.trigger('mouseenter'); // click_event("mouseenter") doesn't work because jquery event handler register mouseenter as mouseover
                 click_event("click");
                 if ($element.is("input, textarea, select") && !$element.is(":focus")) {
                     $element.focus();

addons/web/static/src/js/views/form_relational_widgets.js

@@ -290,6 +290,7 @@ var FieldMany2One = common.AbstractField.extend(common.CompletionFieldMixin, com
             focus: function(e, ui) {
                 e.preventDefault();
             },
+            autoFocus: true,
             html: true,
             // disabled to solve a bug, but may cause others
             //close: anyoneLoosesFocus,