Install tailwindcss

[aleph1ow]

Summary

Manually installs tailwindcss so the relevant config files are copied into the sandbox when running bin/dev. Tailwind now is available. By just editing and saving the template files you'll see the results in the running sandbox. In this pr I use tailwind to fix the search input style that was looking slightly different just after tailwind installation (on focus, a blue ring was shown around the search input field). Even if this pr introduces tailwind it leaves the look completely untouched.

Checklist

Check out our PR guidelines for more details.

The following are mandatory for all PRs:

• [x] I have written a thorough PR description.
• [x] I have kept my commits small and atomic.
• [x] I have used clear, explanatory commit messages.

The following are not always needed:

• 📖 I have updated the README to account for my changes.
• 📑 I have documented new code with YARD.
• 🛣️ I have opened a PR to update the guides.
• ✅ I have added automated tests to cover my changes.
• 📸 I have attached screenshots to demo visual changes.