Allow GravityFormsCLI to be Installed by Packagist

[ibd21]

Description

This PR works to resolve issue #4938, through the support of PRs #47 & #48. With this work, we are allowing the Gravity Forms CLI package to be accessible and installable as a standalone WP-CLI package via WPackagist.

Next Steps needed: Once merged, we need to submit the package to Packagist so users will be able to install it with wp package install gravityforms/gravityformscli.

Related Issue

Closes: #4938

Testing

Testing Requirements

• This needs to be tested in multiple browsers.
• This needs to be tested with both Gravity and Orbital themes.
• This needs to be tested with and without AJAX submission.
• This needs accessibility testing.
• This needs to be tested with different versions of PHP or database servers.
• This needs to be tested with different versions of WordPress.
• None of the above.

Testing Instructions

1. Ensure the code changes here match those that have been suggested

Additional testing -
Once added to Packagist (post-merge), test by running the individual commands:

• wp package install gravityforms/gravityformscli
• wp plugin install gravityformscli --activate
• wp package install https://github.com/gravityforms/gravityformscli.git

QA Tracking Spreadsheet

Checklist

• I've checked the error log to ensure my code doesn't throw any errors.
• I've added a changelog entry (if necessary) and updated the version number in 4 places, run npm install and committed package-lock.json (if necessary).
• I have added a "Documentation Needed" label to this PR (if necessary).

[SherifMesallam]

All good here, I just allowed myself to make some minor modifications, left comments to explain.

[SherifMesallam]

a cleaner exit instead of wrapping the whole class into the check.

[SherifMesallam]

Add all the commands that are actually registered in cli.php

[SherifMesallam]

We need this as a minimum now

[ibd21]

@SherifMesallam -- thanks for jumping in here!! All the changes above look great, will get this merged in now.