Decoupling from WordPress

Summary

In continuation with the epic https://github.com/google/web-stories-wp/issues/2918 "Editor Decoupling", I propose that the decoupling should be done in the following four steps.

1. Move all WordPress-related code from `story-editor` to `wp-story-editor`.

As story-editor package is supposed to be the core editor, it should be free from any WordPress-related code so that it can easily be integrated with any third-party platform. In this step, we would only remove any WordPress-specific code from the story-editor package and this task can be broken down into the following sub-tasks.

[ ] Move all REST API requests logic to wp-story-editor and use more platform-agnostic names for WordPress-specific HTTP headers like X-WP-* used in REST requests
[ ] Move PostLock and StatusCheck components as they are WordPress specific.
[x] Move the “Story Published” dialog to wp-story-editor package.
[ ] Move WordPress media modal logic ( wp.media ) to wp-story-editor.
[ ] Move meta boxes to wp-story-editor.

2. Move all WordPress-related code from `dashboard` to `wp-dashboard`.

Since the dashboard package has a similar code pattern to some extent, our learnings from step 1 would be helpful to move WordPress-specific code to the wp-dashboard package. It may need the following work.

[ ] Refactor dashboard ApiProvider similar to story-editor ApiProvider and move all REST API requests logic to wp-dashboard
[ ] Handling dashboard settings ( analytics, video optimization, etc )
[ ] Handling on "use template” button

3. Prepare an Integration layer API to allow the editor to be integrated with any third-party platform.

After completing step-1 and 2, we should naturally have an integration layer of the core editor and core dashboard with WordPress. However, it would still require some additional tasks for the editor to be integrated with any other platform ( Require Discussion ).

[ ] If there is a need to provide additional configuration/callbacks to handle preview in a non-WordPress environment.
[ ] Maybe provide additional props like onSave, onChange, value, onError, onLoad from the main StoryEditor component.
[ ] Add documentation and maybe some logic to ensure that the REST response is in the expected format provided by the callbacks for both story-editor and dashboard.
[ ] Maybe add bare minimum code to use only filters ( addFilter, applyFilters ) to allow overriding some components like MediaUpload and MetaBoxes from their custom integration ( like wp-story-editor in case of WordPress )
[ ] Maybe introduce our own implementation of Slot/Fill to allow third-party platforms to add additional controls/settings/UI in the editor.

4. Prepare to publish the packages.

[ ] Since the packages can be used outside the scope of WordPress now, we should remove wp- from the package names / find a better name.
[ ] https://github.com/google/web-stories-wp/issues/8577 (due to license)
[ ] Solve any package publishing conundrum.
[ ] Try a basic story-editor integration with some third-party CMS/platform to understand gaps and improvements required.

GoogleForCreators / web-stories-wp