[Investigate] CLI Completions using Cobra

[davidvonthenen]

Some how-tos to take a look at:

• https://blog.devgenius.io/shell-completion-with-cobra-and-go-c8368074d8f7
• https://blog.chmouel.com/posts/cobra-completions/
• https://www.raftt.io/post/auto-completing-cli-arguments-in-golang-with-cobra

[lukeocodes]

Tested this and it works great