Filter locales listed in Administration in order to ensure that the list contains only locales with the correct format

Java 17 apparently added a lot of locales with the script information in it, but our current Locale string parser (actual Apache Commons Lang one) does not support it, so it causes a lot of problems when we try to manipulate such locale. I'm going to add a generic filtering or unsupported Locale format in the API we use to list available Locales.