Starterkits don't add framework assets properly

It was raised in #2831237: Bootstrap modal does not work well with jQuery UI dialog that modals weren't working correctly when using a starterkit sub-theme like LESS or SASS.

This is primarily due to the fact that, when using the CDN, the framework assets are dynamically altered to use a lower weight so they come before the base theme's JS. This gives the "illusion" that "everything works", even though it doesn't for compiled source sub-themes.

The assets should be added to a "framework" library that everything depends on. This way sub-theme's can extend this library with their own assets, but the base theme can still function properly.