Move FilesystemHelper to PSR-4

apps/user_ldap/ajax/wizard.php

apps/user_ldap/appinfo/app.php

apps/user_ldap/lib/FilesystemHelper.php

apps/user_ldap/lib/Proxy.php

apps/user_ldap/lib/User/Manager.php

apps/user_ldap/lib/User/User.php

apps/user_ldap/lib/jobs.php

apps/user_ldap/tests/User/ManagerTest.php

apps/user_ldap/tests/User/UserTest.php

apps/user_ldap/tests/User_LDAPTest.php

apps/user_ldap/tests/access.php

...er_ldap/tests/integration/lib/integrationtestuserhome.php

.../tests/integration/lib/user/IntegrationTestUserAvatar.php