Add support for Spacelift (spacectl)

[damianstasik]

Overview

This PR introduces support for spacectl through API Keys. You need to pass your endpoint URL, API Key ID and Secret, that's it!

Type of change

• [x] Created a new plugin
• [ ] Improved an existing plugin
• [ ] Fixed a bug in an existing plugin
• [ ] Improved contributor utilities or experience

How To Test

There's a handy command to test if the credentials are indeed provisioned:

spacectl whoami

The output should contain JSON with the ID and name of the API Key as well as the endpoint URL.

Changelog