Properties: let the user customize the way Dates/Times are saved

This FR was created to capture the discussion related to letting the user choose in which format the dates of type “date & time” in properties are saved on file.

Currently, we use ISO 8601, extended syntax, second resolution, local time.
While the format chosen for the internal representation may be subject to minor changes in the future, we do not plan for having the users pick a different format. We would like to have fixed format to facilitate interoperability with outside software.

If you would like to write dates in a a different format:

  1. Use the string type and Obsidian won’t touch them
  2. Use the (upcoming) properties API, define a custom type, and handle it with a plugin.

Note this FR is specifically about the way dates are saved. To customize the way they are displayed see