feature #11324 [SecurityBundle] error helper added symfony/symfony#11147 (i3or1s)

This PR was squashed before being merged into the 2.6-dev branch (closes #11324).

Discussion
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[SecurityBundle] error helper added symfony/symfony#11147

Added helper that extracts last authentication error and username.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | [ #11147 ]
| License       | MIT
| Doc PR        | symfony/symfony-docs#3996

Commits
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1722f60 [SecurityBundle] error helper added symfony/symfony#11147

Author: fabpot

Resources/config/security.xml

@@ -48,6 +48,8 @@
         <parameter key="security.validator.user_password.class">Symfony\Component\Security\Core\Validator\Constraints\UserPasswordValidator</parameter>
 
         <parameter key="security.expression_language.class">Symfony\Component\Security\Core\Authorization\ExpressionLanguage</parameter>
+
+        <parameter key="security.authentication_utils.class">Symfony\Component\Security\Http\Authentication\AuthenticationUtils</parameter>
     </parameters>
 
     <services>
@@ -91,6 +93,10 @@
 
         <service id="security.expression_language" class="%security.expression_language.class%" public="false" />
 
+        <service id="security.authentication_utils" class="%security.authentication_utils.class%">
+            <argument type="service" id="request_stack" />
+        </service>
+
         <!-- Authorization related services -->
         <service id="security.access.decision_manager" class="%security.access.decision_manager.class%" public="false">
             <argument type="collection"></argument>