Unique log file name and FAT long file name support

[gongtao0607]

This PR changes the naming schema of the log files and adds FAT LFN support to emfat.

If a proper timestamp is detected in a BB log, the emfat will name it with the timestamp -- so you don't get a collection of rtfl_001 (X).bbl

[rotorflight]

Please strip trailing whitespace on all new lines.
Even better, configure your editor to do it for you!

[rotorflight]

In fact, I should add a check in the PR-CI that would automatically notify the author if there are traling whitespaces or other formatting issues... TBD.

[rotorflight]

I wonder... While we are at it, maybe we can use the craft name instead of RTFL_ prefix.
With spaces and other special characters replaced with _ or something.

[gongtao0607]

Please strip trailing whitespace on all new lines. Even better, configure your editor to do it for you!

Done both. 0a189fa

I wonder... While we are at it, maybe we can use the craft name instead of RTFL_ prefix. With spaces and other special characters replaced with _ or something.

Sounds useful. 207eeaf

Please take another look

[rotorflight]

Sorry to be PITA. What the craft name is empty? Now it would have two underscores.

[gongtao0607]

Sorry to be PITA. What the craft name is empty? Now it would have two underscores.

I thought about it and I thought it's fine as any illegal chars all turn to extra underscores.
Anyway here's the change: f15244f

(Tested with https://github.com/gongtao0607/rotorflight-firmware/tree/RF-flashfs)