Refactor to use script setup

[steersbob]

Resolves #1839

Since Vue 3.3, there is full support for type-only props and event definitions: https://vuejs.org/api/sfc-script-setup.html#type-only-props-emit-declarations.
This allows us to declare composable prop definitions in a much more convenient syntax.

All components are converted to script setup style, and now use a type-only style of props/emit definitions.