Add two-factor authentication settings

- Add settings aside menu entry
- Add two-factor authentication documentation

view/templates/settings/twofactor/verify.tpl

@@ -0,0 +1,22 @@
+<div class="generic-page-wrapper">
+	<h1>{{$title}} <a href="help/Two-Factor-Authentication" title="{{$help_label}}" class="btn btn-default btn-sm"><i aria-hidden="true" class="fa fa-question fa-2x"></i></a></h1>
+	<div>{{$message nofilter}}</div>
+
+	<div class="text-center">
+		{{$qrcode_image nofilter}}
+	</div>
+
+	<form action="settings/2fa/verify?t={{$password_security_token}}" method="post">
+		<input type="hidden" name="form_security_token" value="{{$form_security_token}}">
+
+		{{include file="field_input.tpl" field=$verify_code}}
+
+		<div class="form-group settings-submit-wrapper" >
+			<button type="submit" name="action" id="confirm-submit-button" class="btn btn-primary confirm-button" value="verify">{{$verify_label}}</button>
+		</div>
+	</form>
+
+	<div>{{$qrcode_url_message nofilter}}</div>
+
+	<div>{{$manual_message nofilter}}</div>
+</div>