Make start and end date return a custom class instead of date

[Katsute]

Prerequisites

• I have checked that no other similar feature request already exists.
• I have checked discussions.
• This feature request makes sense for the project.
• I have checked that this feature does not already exist.
• I am running the latest release version.

Feature

For start and end dates, return a custom class that contains the day, month, and year.

Reason

This would reduce confusion with partial start/end dates resolving to January 1 rather than null.

[Katsute]

Possibly extend the Date class and return a NullableDate? Would allow feature to be implemented before v3.

[Katsute]

Return an abstract class of fields instead of class methods

Date {
    year: int?
    month: int?
    day: int?
}

[Katsute]

Added in badcd88

[Katsute]

Nullable date extend Nullable time