Redis tokenization

[FStriewski]

Description:

• Redis has an internal default limit set so that only the first 10 records are returned from the database.
• Redis query logic applies intersection on multi word phrases (AND instead OR logic) - see: https://redis.io/docs/stack/search/reference/query_syntax/

• Changes:

• Override limit with new default, add safeguard, parametrize limit as well as language (optional) for client request
• Parse query string to redis query by replacing whitespace with pipes for non-exact phrases
• Some cleanup