nvs_flash_secure_init() function

- ESP_OK if storage has been initialized successfully. - ESP_ERR_NVS_NO_FREE_PAGES if the NVS storage contains no empty pages (which may happen if NVS partition was truncated) - ESP_ERR_NOT_FOUND if no partition with label "nvs" is found in the partition table - ESP_ERR_NO_MEM in case memory could not be allocated for the internal structures - one of the error codes from the underlying flash storage driver