Make the RSS feed generator use a property of type date for the pubDate attribute

[ZeroKun265]

Is your feature request related to a problem? Please describe. I'm trying to use this to make a kind of blog, i know it's not really the correct use case but it's a bit of an experiment Right now the date depends on when the article file was created, which becomes a problem if you have to reexport (let's say to add a fix to it)

Describe the solution you'd like An option in the settings to override the pubDate, like we have one for the title of a note the time can be a default value, or the time of exporting (or the date and time property could be used)

Describe alternatives you've considered I don't think there are really any alternatives to this

Additional context None