⚛️ Restructure the project folder and files to make it ready for the Directives Hydration

[luisherranz]

Co-authored with @DAreRodz.

These are the things we did here:

• Clean a bit the code related to the Custom Elements Hydration
• Create a separate config for Webpack for the hydration code and the View components
• Enqueue the hydration and View components
• Switch to Preact (compat) on that new Webpack config
• Remove the shared code from the Editor to avoid any @wordpress import
  In doing so, we broke the code of the Editor, but we'll fix that in an upcoming PR

The folder/files should be ready now to add the first implementation of the Directives Hydration.

[DAreRodz]

LGTM! ✅