Equivalent to gh api - making authenticated calls to REST / API endpoints

[jmartasek]

I'd like to have an equivalent functionality to https://cli.github.com/manual/gh_api . In a nutshell - a way to automate Jira even when a particular functionality is not present in jira-cli.

This would create an immediate option to fill in functionality that is missing - both the ones that will be worked on eventually or even niche use-cases.