Fixes to allow for loading full tailwind build for better dev experience

[ptsteadman]

I made the changes in this PR in an attempt to be able to use any tailwind class in development without needing to re-run build:tailwind, as this takes 10-15 seconds on my machine. With these changes, you only need to wait a few seconds for tailwind to build the first time, and you should then be able to freely use tailwind classes. Unused classes are still being properly purged for production builds.

I made the following changes to support this, which I think previously may have made webpack choke or run out of memory when trying to make the build for the dev server:

• removed the variants specified in the tailwind config. I think these are included by default

• changed the purge rule so that it's more focused. I think it was targeting node_modules and .next.

I did a quick check and it doesn't seem to have broken any styles. I am also able to generate a working production build. If you're interested in making this change, I am happy to do a careful comparison to look for regressions and set up a staging site. If not, please let me know what I'm missing, or perhaps this will be useful to someone else.