Add Tailwind

[kmcginnes]

Description

Tailwind CSS is a much better fit for this project than Emotion CSS. It's easier to code review, easier to refactor and split components, results in smaller CSS bundles, is more accepted by the community, and is collated with the components themselves rather than separate files.

I've configured the Tailwind theme to have the same values as the original Graph Explorer theme, so visually, nothing has changed. Once everything is converted over we can consider changing the theme values back to more Tailwind defaults.

To start off the transition, I converted the Workspace components and ModuleContainer components. These are root level components for the general Graph Explorer layout. This works as a great test case to make sure Tailwind has what we need for the conversion and the theme is configured properly.

I made a few small style changes that improve the layout a bit.

• Removed the double bottom border for the top nav bar
• Added a small gap between actions in ModuleContainerHeader
• Added small vertical padding in ModuleContainerHeader so controls won't visually "hit the edge"
• Modified entity filter max heights too more easily see content on small screens
• Fixed horizontal padding in sidebar panels
• Removed unused variants and components

Validation

• Smoke test full app, especially sidebar and workspace layouts

Related Issues

Check List

• I confirm that my contribution is made under the terms of the Apache 2.0
  license.
• I have run pnpm checks to ensure code compiles and meets standards.
• I have run pnpm test to check if all tests are passing.
• I have covered new added functionality with unit tests if necessary.
• I have added an entry in the Changelog.md.