Improve Query Module documentation

1. Finish examples for HQL queries:
   1. Make a join between two objects that are not on the same document and are bound by a property
   2. Find all user pages that don't have have a XWiki.OIDC.ConsentClass xobject
2. Remove the example of query for "Find all user pages that don't have a XWiki.OIDC.ConsentClass object" from XWQL column. Finally place into info box the following text "Since XWQL doesn't support nested selects using the doc.object() syntax, we need to use HQL in the nested select." make it more recognizable.

Note: remove duplication "have" from "Find all user pages that don't have have a XWiki.OIDC.ConsentClass object".