Bug fixes

- Performance improvements from D8 version.
- UX improvement where it defers to HAX if HAX exists

D8 enhancemnets in the selection UI backported. Also takes over and controls the webcomponents settings.

## Autoloader breaking change
This WILL require changes to your autoloader list so when you switch to this you'll need to use the UI to select what you want to use. Almost no one was using this setting previously but its worth noting.

This release adds Drupal 9 compatibility and fixes a few bugs:

Issue #3121753 by katherined: Replace use of deprecated entity.manager service

After linting and some OOP cleanup, we are ready for our 1.0 launch of the SCSS module.

After linting and some OOP cleanup, we are ready for our 1.0 launch of the SCSS module.