Add "plain" date widget

to avoid deform.addCallback() JS for mobile forms

surely there's a better solution, but this works for now...

tailbone/templates/deform/date_plain.pt

@@ -0,0 +1,16 @@
+<div tal:define="css_class css_class|field.widget.css_class;
+                 oid oid|field.oid;
+                 style style|field.widget.style;
+                 type_name type_name|field.widget.type_name;"
+      tal:omit-tag="">
+  ${field.start_mapping()}
+  <input type="${type_name}"
+         name="date"
+         value="${cstruct}"
+
+         tal:attributes="class string: ${css_class or ''} form-control hasDatepicker;
+                         style style;
+                         attributes|field.widget.attributes|{};"
+         id="${oid}"/>
+  ${field.end_mapping()}
+</div>