`UTheme` Support for `props` as well

### Package

v4.x

### Description

Currently it supports `:ui` props. How about some more props as well like `size`, `variant`, etc.

```html
<UTheme size="sm" color="primary">
   // Components inside will use above props
</UTheme>
```

Maybe separate component for this, named `UProp`

### Additional context

_No response_