Add timeout duration to modlog embed

[almostSouji]

It could be computed with an expiration timestamp and message timestamp, but very uncomfortable.
Seeing the duration of a timeout when looking up history can be useful in judging escalation potential.

Ideally, could be added to the expiration line

[JPBM135]

This is actually smt that bothers me since the change to Native Timestamps, but I never questioned it bc I thought you had a reason for it, idk, my suggestion for syntax is:

*Duration:* `10m` (in ten minutes)

[almostSouji]

doesn't need the parentheses, because the native timestamps are distinct enough, short form and in inline code block should be alright, yes