Add littlefs file system and update Sys.IO.FileSystem and stream #171

Job	Run time
build-target (SL_STK3701A, Debug, AzureRTOS)	2m 45s
build-target (SL_STK3701A, Debug, All)	15m 18s
build-target (ST_STM32F769I_DISCOVERY, Debug, ChibiOS)	2m 47s
build-target (ST_STM32F769I_DISCOVERY, Debug, All)	6m 13s
build-target (M5Core2, Debug, ESP32)	4m 57s
build-target (M5Core2, Debug, All)	7m 34s
build-target (NXP_MIMXRT1060_EVK, Debug, FreeRTOS-NXP)	2m 25s
build-target (NXP_MIMXRT1060_EVK, Debug, All)	6m 4s
build-target (TI_CC1352R1_LAUNCHXL, Debug, TI, 915)	3m 12s
build-target (TI_CC1352R1_LAUNCHXL, Debug, All, 915)	6m 18s
	57m 33s

Provide feedback