Allow sorting by specified field for Document Tree macro

The problem is that the document tree uses named native queries, for the reasons explained in https://github.com/xwiki/xwiki-platform/blob/master/xwiki-platform-core/xwiki-platform-index/xwiki-platform-index-tree/xwiki-platform-index-tree-api/src/main/resources/org/xwiki/index/tree/internal/nestedpages/query/queries.hbm.xml#L31 . I see that:

• https://hibernate.atlassian.net/browse/HHH-16 is fixed, and we have it
• https://hibernate.atlassian.net/browse/HHH-1050 is fixed, but we don't have it yet XWIKI-19708

So until we upgrade to Hibernate 6+, the only option is to duplicate the named queries (i.e. have a different named query for each sort variant). I tried to search for a way to reuse named query fragments to reduce duplication, but I couldn't find any good result. So it's doable, but for now it implies adding some code (query) duplication.