Add support for MongoDB Atlas CLI, with environment variable based importing and provisioning

[joqim]

This PR adds support for the MongoDB Atlas CLI. This is different from the core MongoDB CLI.

Core features

• The authentication setup currently is "Public Key" and "Private Key". These are obtained from the Altas organization > Access Manager > API Keys. (One part that's not clear to me yet is, does the key generated here apply to all the projects within the organization? I am failing to a project-specific API generator)
• The shell plugin looks for the Atlas CLI's environment variables and imports into 1Password.
• If there are no environment variables in the current shell session, 1Password prompts the user to manually enter them.
• Provisions the shell plugin for every "atlas" command (except help and version commands) with the environment variables.

Main issues

• Atlas CLI supports config file too, but we don't look for it and import the credentials just yet because it uses a different type of authentication: access token, and refresh token.
• When there is no Atlas CLI config file, but if a MongoDB CLI config file exists, the Atlas commands show a prompt asking if the user would like to import the config file from MongoDB CLI path to the Atlas CLI path. This kind of hinders the 1Password shell plugin's authentication flow.

This is my first time contributing to Shell Plugins, feedback welcome. Thanks, @arunsathiya, for getting me started with 1Password and Shell Plugins.

[AndyTitu]

Code looks good to me overall, I just left a few nitpicks. Awesome job @joqim , thanks for contributing!

[AndyTitu]

I think supporting the environment variables - public/private key-pair - workflow for now is a good approach. We could introduce the config file auth flow further down the line.

[arunsathiya]

Great to see your first PR, Joqim! 🎉

Overall, it looks good to me but I left one comment here to discuss further about the credential name.

[joqim]

Thank you for your feedback. I'll address these recommendations as soon as possible.

[joqim]

I've addressed your changes, please take a look into it.

[AndyTitu]

lgtm

[arunsathiya]

The current changes look good to me too.

[SimonBarendse]

Appreciate the contribution! Thank you for taking the time to submit ❤️

[AndyTitu]

re-approving