prepared query for introducing evaluation expression in query (not fixed second comparation member) [LUCENE-7404]

Lucene is very powerfull but has a limitation very important. It is impossible to use when you want create a query where is a expression inside.
field1: >= field2 where field1 and field2 is not possible.
field1:= field2^2 -4 \*field3
it is pratically impossible to index statically document for this query but it is possible to do 2 things:
1) create a third field hidden here is saved the result.
2) when you use a prepared query , it is saved automatically in a different writer this info that you can save.
Creating a prepared query lucene do all automatically for making this query using indexes.

PS. Pay attention that fields in expression could be not only inside the current document but also in different documents/readers.
It could be used also for join different document types(it is a subcase of the above problem).

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Migrated from [LUCENE-7404](https://issues.apache.org/jira/browse/LUCENE-7404) by Cristian Lorenzetto, updated Aug 05 2016

No source files, tests, or entry points are named. Start by clarifying the proposed prepared-query behavior and whether expressions may reference fields in the current or other documents/readers. Done should include a defined approach for evaluating field expressions and joining different document types.

Written by the indexing model from the issue text.