19256: pkg/tinyusb: add GD32VF103 support r=gschorcht a=gschorcht
### Contribution description
This PR provides the tinyUSB support for GD32VF103 and enables the `tinyusb_device` feature as well as `stdio_tinyusb_cdc_acm` for GD32VF103 boards.
### Testing procedure
```
BOARD=sipeeed-longan-nano make -C tests/shell flash term
```
should work
### Issues/PRs references
Co-authored-by: Gunar Schorcht <gunar@schorcht.net>