fix: Migrator throws Moved error when connecting to cluster

[a9raag]

While connecting to a Redis Cluster Migrator run fails to create_index since the commands are executed using a Redis connection.
In this scenario, there should be some way to distinguish between Redis and RedisCluster in order to avoid:

redis.exceptions.MovedError: 13099 as mentioned in #408 #412
With RedisCluster support there would be an option to execute these commands on primary nodes and we won't run into the MovedError

In this PR:
We can connect with RedisCluster using two ways:

• I have updated get_redis_connection method to allow cluster parameter so it would be as straight forward as using get_redis_connection(host='localhost', cluster=True)
• By providing cluster=True in URL, for example get_redis_connection(url="redis://localhost:6379?cluster=true")
• This would work the same for the URL assigned to REDIS_OM_URL environment variable.

This resolves #408 and
resolves #412

[a9raag]

Hi @chayim @simonprickett,
can you guys please take a look at this?

[simonprickett]

Adding @dvora-h

[a9raag]

We are planning to use redis-om in production and waiting for this fix.
Any input will be appreciated @dvora-h
Thanks :)

[XChikuX]

@chayim @dvora-h I'd love this checked in. If you have the time.

[XChikuX]

You may want to correct the spacing issues here.