chore: remove inline styling & use clsx consistently

[granny]

This PR removes all instances of inline styling. Ternary operator calls in className have been replaced with the clsx() helper method for improved readability.

1. Inline styles calling the margin[...] properties have been updated to use Docusaurus' margin-[...]--sm and margin-[...]--md classes for consistent margin sizes.
2. Inline styles have been merged into pre-existing classes wherever possible.

Only visual inconsistency should be the Icons that originally had 8 pixel margins and the slider markers in the script generator.

[granny]

A dropdown-item-selected class has also been added to this PR

[granny]

The internal styles added to the slider markers has been replaced with flexbox styling. It's now more accurate than how it was before.

Any leftover internal styling and TODOs have now been removed.

[olijeffers0n]

First is the PR, Second is Prod. The Config Pages have changed slightly with respect to margins and highlight colours not being active.

[granny]

1. Selected config options should now properly highlight like before.
2. The margin indenting being off is technically on purpose since docusaurus' built-in margin-bottom--sm class is not 10px, but something closer to 8px. With margin-bottom--xs being closer to 4px and margin-bottom--md being closer to 16px.

[olijeffers0n]

Looks generally good, I’ll review properly soon