markdown element for datetime with automatic timezone conversions

[Die4Ever]

Requirements

• [X] This is a feature request and not a bug report. Otherwise, please create a new bug report instead.
• [X] Please check to see if this request (or a similar one) already exists.
• [X] It's a single feature. Please don't request multiple features in one issue.

Describe the feature you'd like

Currently I don't think there's any way to share datetimes with people without having to worry about timezone conversions. The best you can do is like "24 hours from this post"

would need to be something that renders decently even on clients that don't support it yet