19487: nanocoap: implement extended tokens (RFC 8974) r=benpicco a=benpicco
19808: boards: add ESP32-S3-USB-OTG support r=benpicco a=gschorcht
### Contribution description
This PR provides the support for the [ESP32-S3-USB-OTG](https://docs.espressif.com/projects/espressif-esp-dev-kits/en/latest/esp32s3/esp32-s3-usb-otg/user_guide.html) board.
The SD card can only be used in SPI mode at the moment. As soon as PR #19786 is merged, the SD/MMC support can be enabled and the SD card can then be used in SD mode with 4-bit data bus width.
The display uses uses the ST7789 driver IC that is compatible with the ST7735. For that purpose the ST7735 driver is extended by a pseudomodule definition `st7789` for the ST7789 which is enabled by the board and enables automatically the `st7789` (e57c48a33ee2a869c15603788e5306ba066f91cf). Vise versa, board's `Makefile.dep` enables automatically the `st7789` pseudomodule if the `st7735` is used. The pseudomodule `st7789` is just used to increase the upper limit for supported lines. This change is also part of PR #19807.
~The PR includes a very small documentation fix for ESP32-S3-DevKit board that was noticed during the development of this board definition (1155b6ac1b8efa39d8a0bd7150e602095159fdc1).~
### Testing procedure
The board has been tested with all basic tests for supported hardware including `tests/driver/st3375`:
- [x] tests/drivers/st3375
- [x] tests/periph/gpio
- [x] tests/periph/pwm
- [x] tests/periph/spi
- [x] tests/periph/uart
- [x] tests/sys/usbus_cdc_ecm
### Issues/PRs references
Co-authored-by: Benjamin Valentin <benpicco@beuth-hochschule.de>
Co-authored-by: Gunar Schorcht <gunar@schorcht.net>
This adds a coap_handler_t function that can be used to parse new
subtrees. The subtree information is included in the context pointer of
the call and must be of type coap_resource_subtree_t. This object then
contains the pointer and length of a different coap_resource_t instance.
