[N1QL+FTS] Mandate keyword analyzer for queries that don't use an analyzer

The fields for the following queries need to be set up with "keyword" analyzer within the index for the query to be sargable for the index:

• TermQuery
• PhraseQuery
• MultiPhraseQuery
• FuzzyQuery
• PrefixQuery
• RegexpQuery
• WildcardQuery

This change is necessary to assure consistent results during a covering and a non-covering query scenario when no index options are specified within the SEARCH(..) function.
 
This will also change the behavior for the above mentioned queries, but in a good away - that the user will always see the same result with and without validation.
 

Note: this issue in validation (with a non-covered query) could still happen over certain data with must_not (NEG) over Match and MatchPhrase queries when the user has an index with a field using non-standard analyzer and does NOT specify the index name within options or the analyzer within the query.

See: https://forums.couchbase.com/t/n1ql-search-query-result-varies-depending-on-selected-fields/

Here's an example:

Index: "field": "dept", "analyzer": "keyword" Data: {"dept": "Pre-sales"} 

Query: SELECT * from keyspace WHERE SEARCH(keyspace, "-dept:Sales");

• Search phase would return the document as the match query (which uses the keyword analyzer) wouldn't match Sales with Pre-sales.
• However, during the validation phase - since there's no index context, or analyzer explicitly specified for the match query - the default analyzer is used which causes the document to not be returned for the query.

The workarounds here are these queries ..

SELECT * from keyspace WHERE SEARCH(keyspace, "-dept:Sales", {"index":"index_name"});

SELECT *

FROM keyspace

WHERE SEARCH(keyspace, {"must_not": {"disjuncts":[{"field": "dept", "match": "Sales", "analyzer":"keyword"}]}});