Support Translations for XPages Layout drop down when creating a new XPage Document

The dropdown added in CMS-13433 must be possible to have i18n labels.

In order to provide translated values:

• Add the translation key to /hippo:configuration/hippo:translations/hippo:cms/xpage
• Use the labels of the XPageLayout as key and as value the translated value

Change the org.hippoecm.frontend.plugins.standardworkflow.xpagelayout.XPageLayoutContainer#choiceRenderer to lookup the translation and use that or use the label itself.