Validation of Date/DateTime Relative to Another Date/DateTime

Is your feature request related to a problem? Please describe.
This feature request is not related to a problem. I would like to be able to validate a time fields value based on the value of another required time field value. The use case being for example, having an event content type and specifying a start/end date and time.

Describe the solution you’d like
Either to be able to link the end time value to the start time and say ‘this field must be after the specified field’ or introduce new data types: DateInterval and DateTimeInterval, both being an ordered pair of Dates/DateTimes respectively.

Describe alternatives you’ve considered
At this point I can only think of warning a client that this won’t be checked. Another possibility would be to put a step in the build process to prevent pushing invalid configurations.

Additional context