Valid time interval to NSDateComponentsFormatter

[pyby]

Motivation and Context

Documented in issue #127.

Description

• Check NSTimeInterval is valid to NSDateComponentsFormatter and SRGTimeSliderFormatter(NSTimeInterval seconds) method.
• Add public macro, so that SRGLetterbox library could use it also for additional player UI controls. Valid time duration to NSDateComponentsFormatter srgletterbox-apple#303

Checklist

• The branch should be rebased onto the develop branch for whole tests with last commits.
• The documentation has been updated (if relevant).
• Issues are linked to the PR, if any.