POC: Product traits compatibility

[joshuatf]

Changes proposed in this Pull Request:

This POC adds a trait system for declaring compatibility with other traits. It does the following:

• Sets up an abstraction where traits can be declared
• Moves trait specific methods into that class
• Adds trait metadata to blocks
• Hides blocks when incompatible traits are turned on

Follow-ups to consider for this PR:

• Allow compatibility for existing traits to be filtered (can technically already be done by using the woocommerce_simple_product_traits filter, but might be too complex)
• Replace and deprecate product types (POC in progress)
• Cross-trait compatibility (detecting declared or undeclared compatibility in the opposing trait)
• Server-side validation of trait compatibility

How to test the changes in this Pull Request:

1. Navigate to the Add New Product page with the new product editor experience enabled
2. Click on the "Virtual" toggle
3. Notice that the "Shipping" tab is hidden
4. Optionally make a call to http://test.local/wp-json/wp/v2/template-parts?area=product-form and notice the productTrait data in the block

Changelog entry

• Automatically create a changelog entry from the details below.

Significance

• Patch
• Minor
• Major

Type

• Fix - Fixes an existing bug
• Add - Adds functionality
• Update - Update existing functionality
• Dev - Development related task
• Tweak - A minor adjustment to the codebase
• Performance - Address performance issues
• Enhancement - Improvement to existing functionality

Message

Comment

[github-actions]

Hi , @woocommerce/mothra

Apart from reviewing the code changes, please make sure to review the testing instructions as well.

You can follow this guide to find out what good testing instructions should look like:
https://github.com/woocommerce/woocommerce/wiki/Writing-high-quality-testing-instructions