V15: Show duration on time displays

[iOvergaard]

Description

• Adds helper functions to show a localized duration between two points in time using the Intl.DurationFormat API, which is available in most browsers (Firefox behind a flag).
• Uses the helper function in the <umb-localize-date /> element to show the duration between now and the time in the title attribute

• Improves the UmbLocalizeDateElement to avoid re-rendering
• The longer-term idea is to use this in the schedule publishing modal to let the user know more details about their scheduling

[bjarnef]

@iOvergaard would it be worth looking into this, which does something similar via a duration utils?
umbraco/Umbraco.UI#868

[leekelleher]

Tested out, works great! 🚀