Merge xwiki-platform-query-jpql-parser with xwiki-platform-query-xwql

With the current implementation of XWQL, there is 2 modules:

• xwiki-platform-query-jpql-parser
• xwiki-platform-query-xwql

The JPQL parser is only used internally by xwiki-platform-query-xwql, and the JPQL parser is nothing else than a XWQL parser (so it should be also renamed).

Moreover, the module uses sablecc to generate the parser code, and it does not generate it in an internal package, so the clirr warns about problem when you change the XWQL grammar.

That's why the xwiki-platform-query-jpql-parser module should be integrated into an internal package of xwiki-platform-query-xwql.