[application/connect] simplify connection logic
``application.connect`` now either sets a full featured ``DBAPISession`` to the
``WebRequest`` object or raises ``AuthenticationError``. The creation and usage
of a fake DBAPISession is now handled by ``main_handle_request`` when needed.
This means that fake DBAPISession are no longer tracked by the session manager
and that user are not given anyway to retrieve them for a later request.
This fake DBAPISession is still passed to ``core_handle`` because multiple cubes
like registration or forgotten password need this behavior. We would like to get
ride of it in the future.
This clarification of the connection API greatly simplifies ``DBAPISession``
retrieval//creation process opening the
way to improvements in this area.
Related to #2503918
<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>