Add cluster commands to login and open in browser

[Callum0x50]

This PR adds commands that allow users to login to their clusters by running indev cluster login <clusterName>
Also adds a command to open the openshift console in a browser window by running indev cluster open <clusterName>

While this branch is entirely functional, I'm unsure how I feel about wrapping oc. This obviously puts a requirement for an external binary to be present for these commands to work, and we're also doing os/exec to run the oc commands which I feel a bit uncomfortable doing.

As alternative options I have looked into using the oc or kubectl libraries as an SDK instead, but these both come with big trade-offs and introduce a lot of extra code complexity that I would rather avoid.

Going to have to think this one through and gather some opinions from others before moving on.

[stianfro]

+1 from me

imo the practical merit outweighs the negatives (said from the perspective of someone who will not maintain the feature)

[JonasKs]

I tested it locally, and it works great!
The implementation is maybe as beautiful as you'd like it, but the code is easy to read and reason about. I vote for a quick merge!!

[M99]

Send it! oc is already a requirement if someone wishes to log into their cluster via CLI, so wrapping it is a non-issue in my opinion 🚀