[IMP] web: Kanban: quick create record with more fields

This rev. improves the QuickCreate widget for grouped Kanban views.
It allows specifying in the Kanban arch a form view xmlid, e.g.:

    <kanban quick_create_view="some_form_view_xmlid">
	...
    </kanban>

When this attribute is set, the referenced form view is loaded and
rendered inside the QuickCreate widget. A real FormView widget is
instantiated, meaning that all form view mechanisms are available
in the QuickCreate (modifiers, default_get, onchanges, widgets...).

Task #27475.

addons/web/static/src/xml/kanban.xml

@@ -54,9 +54,8 @@
     </div>
 </t>
 
-<t t-name="KanbanView.QuickCreate">
-    <div class="o_kanban_quick_create">
-        <input type="text" class="o_input" placeholder="Title"/>
+<t t-name="KanbanView.RecordQuickCreate.buttons">
+    <div>
         <button class="btn btn-sm btn-primary o_kanban_add">Add</button>
         <button class="btn btn-sm btn-primary o_kanban_edit">Edit</button>
         <button class="btn btn-sm btn-default o_kanban_cancel ml8">Discard</button>