[Misc] Removed deprecated method and classes

...rc/test/it/org/xwiki/panels/test/ui/NewPagePanelTest.java

...src/test/it/org/xwiki/panels/test/ui/PanelWizardTest.java

...ava/org/xwiki/test/ui/AbstractAdminAuthenticatedTest.java

.../xwiki/test/ui/AbstractStandardUserAuthenticatedTest.java

.../main/java/org/xwiki/test/ui/AdminAuthenticationRule.java

...t/src/main/java/org/xwiki/test/ui/AuthenticationRule.java

...tform-test/src/main/java/org/xwiki/test/ui/TestUtils.java