`--speed` option: duration is always in seconds, even if it is longer than a minute

[darkred]

Currently RHash only shows seconds during the hashing process. I believe that for large files (several GB) it would be useful to show minutes as well. This would give a better sense of how long the process took.

Example (37 GB file / RHash 1.4.4 x64 / win 11) :

Currently:

> rhash --speed test.iso
test.iso 5E8A6FF7
Calculated in 430.593 sec, 88.67 MBps
Total 431.750 sec, 88.51 MBps

My suggestion:

> rhash --speed test.iso
test.iso 5E8A6FF7
Calculated in 7m:10s:593ms, 88.67 MBps
Total 7m:11s:750ms, 88.51 MBps

Thank you.