Allow expires parameter for Http.setCookie(...)

[cuddlecake]

Is your feature request related to a problem? Please describe.
As a web developer familiar with cookies, I would assume Http.setCookie() to have a parameter called expires, as opposed to ageDays.

Describe the solution you'd like
I would prefer an input option for expires to exist, instead of ageDays

Describe alternatives you've considered
Provide a helper function to calculated an appropriate ageDays value, given an expires date.

Additional context
I personally think it is more complicated to derive ageDays from expires than it is to derive expires from ageDays.