Feat: persistent storage of sensor settings in nvs

driver/include/esp_camera.h

@@ -171,6 +171,19 @@ void esp_camera_fb_return(camera_fb_t * fb);
  */
 sensor_t * esp_camera_sensor_get();
 
+/**
+ * @brief Save camera settings to non-volatile-storage (NVS)
+ * 
+ * @param key   A unique nvs key name for the camera settings 
+ */
+esp_err_t esp_camera_save_to_nvs(const char *key);
+
+/**
+ * @brief Save camera settings to non-volatile-storage (NVS)
+ * 
+ * @param key   A unique nvs key name for the camera settings 
+ */
+esp_err_t esp_camera_load_from_nvs(const char *key);
 
 #ifdef __cplusplus
 }