[auth] pass `repo` instead of `vreg` to SessionManager and AuthenticationManager
Those object actually need a repo object to connect and create new session
object. They used to retrieve the repo object using
``vreg.config.repository()``. I'm trying to sanitise the initialisation stack
and get ride of ``config.repository()``, a function that mix factory and cache.
Retrieving the vreg from the repo is trivial (``repo.vreg``) so we now pass the
repo object instead of the vreg.
<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>