[IMP] website_project_issue: my/issues/id form improvements

1/ Display a button for the project_user to come back in backend and
   edit the issue if they want

addons/website_project_issue/views/project_issue_templates.xml

@@ -53,6 +53,7 @@
                                     <div class="col-md-12">
                                         <h4>
                                             Issue <span t-field="issue.id"/> - <span t-field="issue.name"/>
+                                            <a class="btn btn-info" t-att-href="'/web#return_label=Website&amp;model=project.issue&amp;id=%s&amp;view_type=form' % (issue.id)" groups="project.group_project_user">Edit Issue</a>
                                             <span t-field="issue.stage_id.name" class="pull-right label label-info" title="Current stage of this issue"/>
                                         </h4>
                                     </div>