Add duration formatter

[chshersh]

I would really appreciate some formatter for ranges like 1w2d3h4m like this one:

durationF :: Natural -> Builder

But I would like to have an ability to easily interpret 9623 as 9623 minutes or 9623 seconds and format in either 160h23m or 160m23s. Dunno how the resulting interface should look like...

[chshersh]

Seems relevant:

• https://github.com/serokell/o-clock/issues/19

[neongreen]

There's diffF already but I agree that we should have something like this.

[neongreen]

Though obviously baking-in 8 hour days won't be good

[neongreen]

Maybe we can indeed use the o-clock idea with series. I think that instead of type-level lists we can just have a list of predefined (Builder, Int) pairs. @ChShersh what do you think?

[chshersh]

@neongreen Well, since there's o-clock I don't actually need durationF formatter anymore. seriesF is enough to me. I won't use this formatter on something that doesn't represent time. And if I need time I probably will use o-clock. seriesF is already a good reason for me to use package like o-clock. Though, o-clock probably should have Buildable instance but at this moment it's not clear for me which exact Buildable should it use...

[cdornan]

It looks like we don't need this — please feel free to reopen if you disagree.