The Seeed Studio Lora-E5 module only has two control pins.
With the `RadioSwitch` trait the user can implement any method required
by the module/board to control the TX/RX direction of the radio frontend.
* Interrupt handler only triggers a waker:
Do the actual interrupt processing which involves SUBGHZ SPI coms in the task.
* Do not require a static state for the constructor.
* Remove unsafe from construcor.
It was only useful for doing #[embassy_executor::main(config = "config()")]`. Now that
it's gone, it makes more sense to build the config in main directly.
