Change Reset behavior to be more consistent with Redis

[Mathos1432]

1. In Redis RESET doesn't add the other nodes to a ban list.

• Updated to remove the banlist entirely.

2. Close gossip connections when a RESET comes in

• Added a test to verify that the node isn't getting any gossips after a reset.

3. Don't allow RESET when a node has keys in its assigned hashslots.

• Iterate over the main store and the object store until you find a slot that has a key.

Verified by running the updated test before the fixes (failed) and after the fixes (passed)

[vazois]

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