Add support for the relative time human requests (yesterday, two weeks ago, etc.)

[kayrus]

The packages search hasn't gave any results. There is only the opposite logic package https://github.com/dustin/go-humanize.

Ideally there should be a way to replicate journalctl --since yesterday (https://github.com/systemd/systemd/blob/8f5d6a044bba001749e0826afe05ae505b4afda3/src/basic/time-util.c#L533).

[kayrus]

An alternative:

$ hermesctl list --time-start `date --iso-8601=sec -d "2 weeks ago"`