Moving of this repo into the main Slint repo

[NigelBreslaw]

Hi Everyone,

We are hours away from having the Material 3 components hit 1.0 and be ready to launch. We've decided that we can better support and maintain the components in the main Slint monorepo at https://github.com/slint-ui/slint and you can find the Material 3 design system in https://github.com/slint-ui/slint/tree/master/ui-libraries/material

The entire history along with all contributions has moved as well.

As of today we will then archive this repo. Sorry for any inconvenience, but we wanted to do this before 1.0 ships and the number of users is relatively small.

Best regards,
Nigel