f3probe: add --verbose flag

[AltraMayor]

The --verbose flag addresses the following demands:

1. Providing (some) progress feedback. See issue Progress bar in 2019? #122;
2. Reporting blocks that cannot be read or written. See issue f3probe "device is damaged" could use more details #119;
3. Helping to diagnose how some fake drives evade f3probe's algorithm. See issue 2x Scam SSDs that trick f3probe (but not f3write) - avaliable to anyone who wants to use them to improve f3 #247 for an example.