Add littlefs file system and update Sys.IO.FileSystem and stream #177

Job	Run time
build-target (SL_STK3701A, Debug, AzureRTOS)	2m 37s
build-target (SL_STK3701A, Debug, All)	7m 24s
build-target (ST_STM32F769I_DISCOVERY, Debug, ChibiOS)	4m 28s
build-target (ST_STM32F769I_DISCOVERY, Debug, All)	7m 39s
build-target (M5Core2, Debug, ESP32)	6m 32s
build-target (M5Core2, Debug, All)	7m 25s
build-target (NXP_MIMXRT1060_EVK, Debug, FreeRTOS-NXP)	3m 19s
build-target (NXP_MIMXRT1060_EVK, Debug, All)	7m 6s
build-target (TI_CC1352R1_LAUNCHXL, Debug, TI, 915)	2m 35s
build-target (TI_CC1352R1_LAUNCHXL, Debug, All, 915)	5m 56s
	55m 1s

Provide feedback