Format output as JSON

Created by: mboutet

Describe the feature or problem you'd like to solve I'm trying to use glab in my CI, but the lack of easily parsable output makes it difficult to work with. Right now, I use regex to extract what I need, which is more complicated than it needs to be.

Propose a Solution A flag such as --output=json|yaml|... or --format=json|yaml|....

As an alternative, I could directly use the GitLab API, but I find the glab CLI to be far more elegant and easier to understand.

Additional context I've searched the issues and PRs and could not find something that matches what I describe.