Make the node crash with a fatal error if the storage path becomes unavailable

[Alexey]

The check for drive unmounts has been implemented in the v1.11.1

@littleskunk

Periodic Filesystem Check
On startup, the storage node will write a file and once per minute, it will try to read this file. If the hard drive gets disconnected from the storage node this check will fail and the storage node will error out instead of getting disqualified for failing audits.