More restrictive vote command duration

[KasperiP]

Currently there is possibility to input negative values for duration which makes the vote duration 100+ years although vote instantly ends. I dont think this is intended behavior / there shouldn't be need for longer votes than max 1month or so?

[lajp]

This is a known issue which I have ignored thus far and will most likely keep doing so.
Feel free to fix it however if you want.