Add ctp get command, to show a single control plane.

[AlainRoy]

Description

This adds a new command: "ctp get", which shows details of a single control plane. It shows the details as a table with a single row, similar to kubectl.

I have:

• [X] Read and followed Upbound's contribution process.
• [X] Run make reviewable to ensure this PR is ready for review.
• [ ] Added backport release-x.y labels to auto-backport this PR, as appropriate.

How has this code been tested

Tested manually. I didn't see tests for most commands, so I followed suit.

Sample output:

up alpha ctp get demo-ucp-idp
NAME           ID                                     STATUS
demo-ucp-idp   ffa9da67-8439-4b7d-a466-e1fb635f6ebe   ready 

Future Work

• Add 'get' for other types (e.g. organizations, robots...)
• Add the ability to output in JSON or YAML, to see more details