Add kurtosis context rename to allow renaming every Kurtosis context except default

[mieubrisse]

Background & motivation

I have both my Google and Github accounts linked to Kurtosis, so I have two Cloud instances. I frequently get confused which is which, and would like to be able give them human-friendly names.

Desired behaviour

There's a kurtosis context rename which allows me to rename any Kurtosis context except default (which I think is a hardcoded string in Kurtosis itself) to a human-friendly name of my choosing.

Maybe something like:

kurtosis context rename cloud-d8269a69644e47479d9268e1f0b3e227 cloud-github

How important is this to you?

Painful; the lack of this feature makes using Kurtosis frictionful.

What area of the product does this pertain to?

CLI: the Command Line Interface