elements: refactor WCCSS preprocesser to handle dark mode better

# What

Re-writes the structures and functions inside WCCSS to a more modern, class-oriented system. Too many details were getting lost in the noise, and the idea that these were “abstractions” that I needed to ignore just wasn’t cutting it. Re-writting the Patternfly reader so that it was clear what was happening at each step (pulling in the content, then traversing it to determine the `:root` CSS values) made the next step much easier.

Dark mode analysis has been added: the `html[theme="dark"]` selector is automatically detected if present in a component’s ReactCSS variant, and ported correctly to a web-component oriented format.

ak-button’s CSS has been re-activated as a pure WCCSS product, and it works correctly.

ak-tooltip was too heavily customized; it’s effectively our own code now, so it will remain “overridden.” (Also, it was misspelled “overriden,” which I have corrected.)

# Why

Because the burden of hand-maintaining component with dark mode was become onerous, and this will accelerate the production of new components with dark mode attached.

Author: kensternberg-authentik