[ADD] web: fields char and many2one can take an option barcode_events

This allows to detect barcode scans while the focus is in such a field.
It is not the default behaviour because buffering keystrokes to see if
they are a barcode then releasing them if they aren't isn't trivial
(it is impossible to trigger a native keyboard event).

addons/web/static/src/xml/base.xml

@@ -666,6 +666,7 @@
     <span t-att-class="'oe_form_field '+widget.widget_class" t-att-style="widget.node.attrs.style">
         <t t-if="!widget.get('effective_readonly')">
             <input t-att-type="widget.password ? 'password' : 'text'"
+                t-att-barcode_events="widget.options.barcode_events"
                 t-att-id="widget.id_for_label"
                 t-att-tabindex="widget.node.attrs.tabindex"
                 t-att-autofocus="widget.node.attrs.autofocus"
@@ -820,6 +821,7 @@
                 class="oe_m2o_cm_button fa fa-external-link" draggable="false"/>
             <div>
                 <input type="text"
+                    t-att-barcode_events="widget.options.barcode_events"
                     t-att-id="widget.id_for_label"
                     t-att-tabindex="widget.node.attrs.tabindex"
                     t-att-autofocus="widget.node.attrs.autofocus"