OAK-10141: relevance on queries involving dynamic boost sometimes differ from lucene

[fabriziofortino]

• refactoring of full-text tests to share them between lucene and elastic
• fix an issue on elastic where full-text queries wrongly assigned the boost factor on specific fields
• fix relevance in Elastic when dynamic boost is enabled. The dynamic terms need to be de-boosted (as it happens in lucene). To properly address the issue, a new field has been created. This is not a breaking change since the queries won't complain in case the field is not yet there. A reindex is required to get the correct relevant results.

[nit0906]

lgtm - If possible, can we check that we didn't miss any test during the refactoring ?

Maybe just compare the list of tests from a build on trunk vs this ?

[fabriziofortino]

@nit0906 the list of tests is not the same as before. While refactoring, I noticed duplicate tests that I removed and added new tests. To easily see what was done in the refactoring, you can have a look at the specific commits in this PR. Every commit has a clear description and you can see the relevant changes in smaller chunks.