Add additional files to the fs to prevent OS indexing

[microbit-carlos]

For example .metadata_never_index and .feventsd/no_log in macOS.

Creating the issue here mostly to be able to log somewhere a few useful links. We should suggest this upstream at some point, although it should definitely be behind compile time flags, as it can have a significant impact on bootloader/interface flash consumption.

• adafruit/circuitpython@a7e3c74
• https://github.com/adafruit/circuitpython/blob/92c121b1aeb49c3688c152d78e57f58a6f711def/supervisor/shared/filesystem.c#L129-L140