[Feature-Request] Support for uploadfs to UserData memory area (LittleFS)

[CSC-Sendance]

Context

The nordic nrf52 series supports a "user data" memory area that contains a littlefs file system (see https://learn.adafruit.com/bluefruit-nrf52-feather-learning-guide/hathach-memory-map ). There is also an Adafruit library for it called "InternalFileSystem".

Request
There is currently no support to upload a LittleFS as a platformIO task called "uploadfs". E.g. ESP8266 have this feature (see here) which will cause an "Upload Filesystem Image" to appear in Tasks > env > Platform

Comments
I am not accustomed to the inner workings of pio but may try to create a pull request upon a discussion what one must accomplish to implement this feature.

Issues

• After some investigations, I found that flashing the bare filesystem may override existing BLE-bonds. This may not be an issue though, if the BLE controller just reinitializes the necessary directories etc. if they were deleted.