Add simple querystring search

[zarnor]

Add SimpleQuerystringSearch() method to allow using elastics simple_query_sring syntax.

Simple query string reference: https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-simple-query-string-query.html

Example:

SearchResult result = service
   .SimpleQuerystringSearch<ArticlePage>("(bacon | ham) melt -cheese")
   .GetResults();

Allowed operators can be limited with allowedOperations parameter:

SearchResult result = service
   .SimpleQuerystringSearch<ArticlePage>("\"bacon melt\" sandwi*",
      defaultOperator: Operator.And,
      allowedOperators:
         SimpleQuerystringOperators.Prefix |
         SimpleQuerystringOperators.Phrase);
    )
   .GetResults();

[otanum]

Release 11.7.3.163 @zarnor