zephyr: Add initial ubluetooth module integration.

Currently only advertising and scanning are supported, using the ring
buffer for events (ie not synchronous events at this stage).

The ble_gap_advertise.py multi-test passes (tested on a nucleo_wb55rg
board).

Signed-off-by: Damien George <damien@micropython.org>

ports/zephyr/CMakeLists.txt

@@ -40,6 +40,7 @@ set(MICROPY_SOURCE_PORT
     machine_i2c.c
     machine_pin.c
     machine_uart.c
+    modbluetooth_zephyr.c
     modmachine.c
     moduos.c
     modusocket.c

ports/zephyr/main.c

@@ -49,6 +49,7 @@
 #include "py/stackctrl.h"
 #include "lib/utils/pyexec.h"
 #include "lib/mp-readline/readline.h"
+#include "extmod/modbluetooth.h"
 
 #if MICROPY_VFS
 #include "extmod/vfs.h"
@@ -168,6 +169,9 @@ int real_main(void) {
 
     printf("soft reboot\n");
 
+    #if MICROPY_PY_BLUETOOTH
+    mp_bluetooth_deinit();
+    #endif
     #if MICROPY_PY_MACHINE
     machine_pin_deinit();
     #endif