Add Flowbite to project

[reefdog]

We're using Tailwind CSS, and were discussing the cost:benefit of using a component library like Tailwind UI or Flowbite.

We've decided the licensing around Tailwind UI is concerning: they claim it's perfectly valid to use their components in an open-source project, but with a list of restrictions on use that mean it's only actually as safe as they make it. (If we use every component in the library, and someone looks through our markup, extracts each component, and creates a library… have we enabled a violation of the license? Obviously not, but it'd be no fun to prove it!)

So, while Flowbite is not as polished as Tailwind UI, the non-Pro version is actually MIT-licensed and safe to use in our project.

This issue is for adding the actual library to the project.

[reefdog]

I wanted to document here in this issue that getting Flowbite working involved two headaches:

1. Flowbite's JavaScript-using components (like Modal and Dropdown) are currently incompatible with Turbo. They initialize on pageload, but upon first Turbo-fired page navigation, they stop working. Resolving this required patching Flowbite itself (034c8c5).
2. Using Flowbite — which extends Tailwind CSS itself — ultimately necessitated ditching the Rails 7 import-maps lifestyle in favor of standard JS/CSS bundling (Revert back to jsbundler/cssbundler #191).