Makes it possible to browse eMMC partitions and dump data from them.
Since we're manually parsing FAT partitions, reading files protected by the FS sysmodule at runtime is possible.
Takes care of retrieving a FsStorage object for any FAT eMMC BIS partition, mounting it via FatFs and creating a virtual devoptab device that can be used to carry out FS operations. All write operations have been stubbed, disabled or ifdef'd out of the code.
Other changes include:
* cert: update code to use the new BIS storage interface.
* defines: remove BIS_SYSTEM_PARTITION_MOUNT_NAME macro.
* devoptab: slightly improve macros.
* devoptab: add operation table for FatFs devices.
* devoptab: add rodev_fstat().
* devoptab: add devoptabMountFatFsDevice().
* fatfs: update diskio code to use the new BIS storage interface.
* fatfs: update configuration.
* save: update code to use regular C I/O calls instead of FatFs calls.
* tik: update code to use the new BIS storage interface.
* utils: remove eMMC BIS System partition (un)mount code.
