Allow SDCARD to be used for config/eeprom storage.

* On boot SPI or SDIO is initialised.
* Filesystem is initialised (including creation of blackbox freespace
file)
* Empty config file is created if it doesn't exist, or read if it does.
* If config is invalid/empty then config file is written to, then read
back and verified.

Enable as follows.

target.h:

target.c:
uint8_t eepromData[EEPROM_SIZE];

Changes:
- Replace boolean init flags with single initFlags variables.
- Avoid unused variable warnings.

src/main/cli/cli.c

@@ -3315,6 +3315,7 @@ static void cliRebootEx(bool bootLoader)
     bufWriterFlush(cliWriter);
     waitForSerialPortToFinishTransmitting(cliPort);
     stopPwmAllMotors();
+
     if (bootLoader) {
         systemResetToBootloader();
         return;