Style: Make components themeable (#5908)

## Summary

Replace color/dark-color pairs in components with design tokens to allow
for easy overriding.
<!-- Also standardizes the icon pattern to simplify the tailwind config.
-->

## Changes

- **What**: Token based colors, for now, mostly.
- **Breaking**: Got approval from Design to collapse some very similar
pairs of colors that seem to have diverged in implementations over time.
Some of the colors might be a little different, but we can tweak them
later.

## Review Focus

Still have quite a few places from which to remove `dark-theme`, but
this at least gets the theming much closer.
Need to decide if I want to keep going in here or cut this and do the
rest in a subsequent PR.

## Screenshots (if applicable)

<!-- Add screenshots or video recording to help explain your changes -->

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5908-WIP-Make-components-themeable-2816d73d365081ffbc05d189fe71084b)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>

tests-ui/tests/renderer/extensions/vueNodes/components/LGraphNode.test.ts

@@ -171,8 +171,7 @@ describe('LGraphNode', () => {
     mockData.mockNodeIds = new Set(['test-node-123'])
     const wrapper = mountLGraphNode({ nodeData: mockNodeData })
     expect(wrapper.classes()).toContain('outline-2')
-    expect(wrapper.classes()).toContain('outline-black')
-    expect(wrapper.classes()).toContain('dark-theme:outline-white')
+    expect(wrapper.classes()).toContain('outline-node-component-outline')
   })
 
   it('should apply executing animation when executing prop is true', () => {