Allow Usage of ISO 8601 in the frontmatter

[Xanaxus]

Please select if your request is either something new or an enhancement

• [x] Enhancement of an existing Feature.
• [ ] Request of a new feature.

Please select the area your request applies to. (Multiple selections are Possible. You can leave blank if you're not sure.)

• [x] Workspace - VSCode workspace, vaults, Intellisense/autocomplete, Dendron settings
• [ ] Lookup - Dendron's Lookup Command
• [ ] Views - Dendron Preview, Tree View, Side Panels in the UI
• [x] Schema - Dendron Schemas
• [ ] Pod - Data import from / export to Dendron
• [ ] Publish - External Site Publish
• [ ] Markdown - Markdown features, such as syntax support and features

Is your feature request related to a problem? Please describe

It would be nice to have ISO 8601 in the updated and created slot. As the current time stamp dosen't.

[SeriousBug]

Thanks for the suggestion!

[sinewalker]

Plus one. There are other settings available in Default Timestamp decoration format but they are all American month/day/year, and while there is a 24-hour time option, it has no date part. https://xkcd.com/1179/