Collapse date ranges

[alexpovel]

Collapse date ranges if they only span a single day, such that e.g. July 31, 2020 - July 31, 2020 becomes July 31, 2020.

[alexpovel]

As an addition, there should be a way to specify whole months, as opposed to exact days. For example, if a thing occurred in July 2020, currently a day has to be specified even though that might not reflect reality.

The same idea applies to years.

In my own use cases, I'd use 2020-01-01 to mean the year 2020, for example. However, we can't really apply such magic since people might actually want that date to work normally, of course. An additional flag like ignore_day_of_month or similar could work, but we also don't want to mess with the original schema too much.