Add LittleFS and FFat filesystem support

Right now the only support filesystem builder tool is SPIFFS via mkspiffs

https://github.com/platformio/platform-espressif32/blob/6c30a4a4b51fa33cf7a45f2b65328a5ad10e75b0/builder/main.py#L167-L168

https://github.com/platformio/platform-espressif32/blob/6c30a4a4b51fa33cf7a45f2b65328a5ad10e75b0/builder/main.py#L196-L208

this should be expanded so that, as for the ESP8266 other filesystems are supported. Per https://github.com/lorol/arduino-esp32fs-plugin and Arduino-ESP32, SPIFFS, LittleFS and FFat filesystems are supported.

For generation of the image, analogue to mkspiffs and mklittlefs, the tool mkfatfs may be usable. The version used in the Arduino IDE is at https://github.com/lorol/arduino-esp32fatfs-plugin/tree/master/extra (refer package for mkfatfs)

[maxgerhardt]

For reference, I’ve created a project at https://github.com/maxgerhardt/pio-esp32-fatfs-example with a modified https://github.com/maxgerhardt/platform-espressif32 that allows using FatFs. The only thing that’s missing is that tool-mkfatfs gets uploaded and referenced as a package, I’ve just thrown it into the project folder there.

[Algonsi]

Thank you very much for your fast and accurate help. You made me realize that I had set board_build.filesystem = ffat When I have corrected it to ‘fatfs’, the problem disappeared. Thanks again, you do a great job.