[entity] add a "repo_side" parameter to `_cw_dont_cache_attribute`
This parameter (defaulting to `False`) is used to inform cubicweb that we really
really do not want to cache a value during creation or update. This will be used
by a storage that may do very specific processing on attribute values that result
in a stored value different than the provided one (e.g. BFSS `fs_importing`
mode).
<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>