* Introduce a trait for DMA channels
This trait is then used to hold types related to the particular DMA channel. This change allows us to simplify user-facing types.
* Remove private type from I2s
* Remove redundant spi3 example, update examples
* Merge markdown sections
* Add changelog entry
* ground work for async dma (gdma only atm)
* Add async DMA (GDMA) - esp32c3/esp32c2
* Add Async SPI impl for esp32c3/c2
* Remove private modules from DMA
* add async spi example for esp32c3
* Switch to assoc wakers instead of a static array
* add support for esp32/esp32s2
* add support for esp32s3
* run fmt
* add c2 example, fix CI
* Remove redundant comments