INT-2799 Changes the default RedisTemplate to a StringRedisTemplate. This causes issues with setting the serializers because this could mean we are using a StringRedisTemplate with non-String serializers. While this works fine with current spring-redis releases; it could cause problems with future releases and just "doesn't seem right".
In any case, these (serializer) attributes on the adapters are really just a convenience. It is just as easy to wire up an external RedisTemplate with the required serializers, and inject that instead.
This has the added advantage of removing the logic of testing for whether or not an external template has been injected.