[views/templates] provide a modal main template (closes #3274672)
The current NonTemplatableViewTemplate may seem to provide the desired
feature if a '__notemplate' is provided in the form, unfortunately,
it:
* wraps the view in a spurious div
* calls view.set_stream(), which has the effect of wiping any js/css
resource recorded until then by the view, leading to hard-to-track
missing resources symptoms
<table class="attributeForm" style="width:100%;"
tal:attributes="id tab_id | nothing;
class tab_class | nothing;">
<tr tal:iter="widget lines">
<th class="labelCol" tal:content="structure python:widget.render_label(entity)">attrname</th>
<td tal:define="error python:widget.render_error(entity)" style="width:100%;"
tal:attributes="class python:error and 'error' or nothing">
<div tal:replace="structure error">error message if any</div>
<div tal:replace="structure python:widget.edit_render(entity)" >widget (input, textarea, etc.)</div>
<div tal:replace="structure python:widget.render_help(entity)">format help if any</div>
</td>
</tr>
</table>