Add FATFS build test workflow #203

Job	Run time
Build wolfssl (ubuntu-latest)	52s
Build wolfssl (macos-latest)	46s
Build wolfssh (ubuntu-latest)	17s
Build wolfssh (ubuntu-latest, --enable-all)	19s
Build wolfssh (ubuntu-latest, --enable-sftp)	23s
Build wolfssh (ubuntu-latest, --enable-scp)	18s
Build wolfssh (ubuntu-latest, --enable-shell)	17s
Build wolfssh (macos-latest)	43s
Build wolfssh (macos-latest, --enable-all)	39s
Build wolfssh (macos-latest, --enable-sftp)	1s
Build wolfssh (macos-latest, --enable-scp)	3s
Build wolfssh (macos-latest, --enable-shell)	1s
	4m 39s

Provide feedback