esp32: Add MICROPY_HW_USB_CDC macro for native USB-CDC serial.

This fixes issue of ESP32-S3 switching its config over to USB serial/JTAG
instead of native USB.

The the existing logic was hard to follow, adding this config macro makes
it easier to see which USB is in use and to have board definitions that
enable/disable different USB levels.

This commit also drops (nominal) support for manually setting
CONFIG_ESP_CONSOLE_USB_CDC in sdkconfig. No included board configs use this
and it didn't seem to work (if secondary console was set to the default USB
Serial/JTAG then there is no serial output on any port, and if secondary
console was set to None then linking fails.) Can be re-added if there's a
use case for it.

This work was funded through GitHub Sponsors.

Signed-off-by: Angus Gratton <angus@redyak.com.au>

ports/esp32/main.c

@@ -101,7 +101,7 @@ void mp_task(void *pvParameter) {
     #endif
     #if MICROPY_HW_ESP_USB_SERIAL_JTAG
     usb_serial_jtag_init();
-    #elif CONFIG_USB_OTG_SUPPORTED
+    #elif MICROPY_HW_USB_CDC
     usb_init();
     #endif
     #if MICROPY_HW_ENABLE_UART_REPL