BREAKING: Change shadow API to return state object

...not entire MQTT message.

Previously GET and UPDATE_ACCEPTED messages would return an object like this:
```json
{
  "state": {
    "reported": { ... },
    "desired": { ... }
  }
}
```

Now they will return an object like this:
```json
{
  "reported": { ... },
  "desired": { ... }
}
```

This is necessary for the upcoming Azure shadow implementation.

Shadow update API is also being changed to take reported state only.

CL: BREAKING: Change shadow API to return state object

PUBLISHED_FROM=8706cfce56532d3f037d9940dbdcec891d43bb0a

fw/platforms/esp32/sdkconfig

@@ -16,7 +16,7 @@ CONFIG_ESP32_ENABLE_COREDUMP_TO_NONE=
 CONFIG_ESP32_ENABLE_COREDUMP=y
 CONFIG_ESP32_CORE_DUMP_UART_DELAY=0
 CONFIG_ESP32_CORE_DUMP_LOG_LEVEL=1
-CONFIG_SYSTEM_EVENT_TASK_STACK_SIZE=3072
+CONFIG_SYSTEM_EVENT_TASK_STACK_SIZE=4096
 CONFIG_TASK_WDT_PANIC=y
 CONFIG_ESP32_DEEP_SLEEP_WAKEUP_DELAY=0