Add support for Redis JSON

[Dgramada]

This is a follow up pull request to #3327 that handles the new JSON API for Spring Data Redis.
It builds upon the command layer from the referenced PR and adds API for the template layer.

Notes:

• BoundJsonOperations is not included yet. Once a version of JsonOperations is approved, the bound operations can be included in this branch.
• RedisJsonTemplate initially felt like a good idea. It creates a separation of concerns, which is nice because the new JSON API does not pair well with a specific V type unlike the other data types in RedisTemplate. However, RedisJsonTemplate feels a little off and maybe a more elegant solution could be derived. It feels more like a configuration class. Maybe we could rename it to RedisJsonConfig. This would also promote developers to inject JsonOperations directly.
• RedisJsonSerializer does not extend RedisSerializer, due to it bringing a lot of functionality that doesn't add any value to the JSON serialization. Furthermore, keeping them separate gives separation of concerns. Also Jedis and Lettuce do not provide byte[] APIs for the JSON commands in Redis, thus making RedisSerializer incompatible.

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[mp911de]

Here's an initial round of review feedback.

[mp911de]

Let's default to String serializers. Zooming out, a constructor RedisJsonTemplate(RedisConnectionFactory) with String and a default JSON serializer(Jackson 2/Jackson 3) makes sense. Also, a constructorRedisJsonTemplate(RedisConnectionFactory, RedisSerializer, RedisJsonSerializer)` as alternative to provide serializers.

Moving off mutable state is a good thing. We can still keep transaction support but even for transactions I am not sure we should do this.

[viktoriya-kutsarova]

After discussing with @mp911de and @Dgramada, we agreed to mark transaction support as out of scope for this feature. @Dgramada will remove the related code.

We also agreed that RedisJsonTemplate should default to a string serializer for keys and RedisJsonSerializer for values (the actual JSON). @Dgramada explored the proposed constructor approach, but it led to this line:

this.keySerializer = (RedisSerializer<K>) RedisSerializer.string();

which would break if K is anything other than String. Following @mp911de's suggestion, we'll explore a static factory method next and see whether it surfaces any other issues.