Add dialect support for RediSearch queries

[DvirDukhan]

Version: What redis-py and what redis version is the issue happening on?
RediSearch>=2.4.3

On RediSearch 2.4.3 we will introduce a new DIALECT command argument for queries (FT.SEARCH, FT.AGGREGATE) this will allow to process queries either by the current dialect (RediSearch 2.2.x) or the new dialect introduced on RediSearch 2.4.2.
New dialect features:

1. parameterized queries
2. VSS
3. Improved syntax behavior as introduced at https://github.com/RediSearch/RediSearch/releases/tag/v2.4.2