Check if the boost library date_time can be replaced

[mvieth]

    > i thought there is an opportunity to get rid of date_time incluclusion, but there's no easy way to do it

I think date_time is mostly needed for to_iso_string and local_time, to create a string representing the current time (for filenames etc), right? Maybe std::strftime or std::put_time can replace that?

Originally posted by @mvieth in #5204 (comment)

We are using some functions from boost's date_time library. It would be great if we can replace some or even all of them with functions from the standard library. If we don't need date_time any more, we can remove it as a dependency.

[mvieth]

Done by #5596