Publish the design documents for datetime formats

[dkhalanskyjb]

Often, library authors are asked to change some aspects of the behavior of our entities. Sometimes, we can't remember all the considerations that we had when deciding how something should work and can't determine whether the suggestion is something we already considered; sometimes, we do remember it but have to repeat our answers time and again in different places, and it would be nice to be able to refer those interested to a central place that explained our reasoning in a structured manner. As the memory of designing datetime formats is recent, we can fairly easily document our thought process and the alternatives that we considered at every point.