Plugin improvements and additions, dependency installer, bugfixes.

What's inside

Feature breakdown

Improvements

• Simplify configuration syntax: optional complex structure with position and implementation.
• Add API for direct interaction with source class (can be used to replace the source one with your custom one or wrap the source one into a HOC of your choice)
• Allow plugging into reducers and creating new ones.
• Allow changing reducers' initial state
• Introduce extensions' dependency installer
• Restructure config folder
• Cut stripe payment method out (convert it into an extension)

Bug fixes

• Fix context loss in 'get' handler
• Fix service worker builder unable to find extension-import-injector
• Explicitly disable fallback plugin in core mode
• Fix extension filtering condition for sw development
• Fix extensions not working properly with things that are instantiated on export (like queries, utils and dispatchers)
• Fix parent theme and make it optional in scandipwa.json
• Fix store import from media breaking the application when extensions are applied to something related