Mantine.dev add-on

[icflorescu]

I know not using tailwind is frowned upon by a lot of people nowadays, but in my biased opinion there are good React UI frameworks out there, and Mantine is one of the best (shameless plug: I'm one of the contributors and the creator of Mantine DataTable).

It would be great if we could find a way to provide a Mantine add-on to create-tsrouter-app at some point, once TanStack/router#2589 and TanStack/router#3023 are addressed.

I'd like to give this a stub at some point in the near future if you like the idea.
If not, I could simply create a starter template.

[jherr]

Feel free to PR an add-on.