MRG: adjust Signature::name() to return Option<String> instead of filename() and md5sum()
#5980
| Job | Run time |
|---|---|
| 10m 27s | |
| 6m 59s | |
| 20m 48s | |
| 13m 20s | |
| 9m 28s | |
| 6m 50s | |
| 1h 7m 52s |