Load a setup configuration file from the SDCard on start

[GrazianoCapelli]

We need to implement a method to load the setup configuration file on SDCard.
The Air Data Computer could search the file CONFIG.CFG into the SDCard on start (a one-time operation, when the user powers the device).
If the file is found, the firmware executes the commands in the file, in the same order they are written.
No additional commands are needed to implement this feature.

Different SDCards can have different setup configuration, depending on the CFG file.

Any software interface can override these settings by send a different configuration as soon as they are connected.

[GrazianoCapelli]

Feature implemented.
The setup presets file is CONFIG.CFG; it must be in the root directory of the SD.

Successfully tested with the following content:
$DTQ,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
$FMQ,DEL,NEWFILE.CSV
$FMQ,NEW,NEWFILE.CSV
$LCS,NEWFILE.CSV
$DFS,0.5,0,0