This is needed in order to colorize it as next step.
We use conventions in output messages such as

>>> This is an action
*** This is a warning
[ERR] This is an error
[OK] That's fine

And so forth, so that a color will be associated checking the first
three chars.

Slot zero was hardcoded (!)

Open slots are slots found in importing or migrating slot when a
cluster check is performed.

redis-trib: create subcommand fixed calling node info loading method. Was needed after recent refactoring.

redis-trib: initial working implementation of cluster rehashing, more work needed to make it more correct, more reliable.

redis-trib: initial slots allocation strategy, still to improve for better balancing when there are just a few slots to move.

redis-trib: minor refactoring creating a method to load the cluster information starting from a single node