Add time debugging for validation start_date

[bakhterets]

var ErrIncidentStartDateInFuture = errors.New("event start_date should not be in the future")

example:

func validateEventCreation(incData IncidentData, logger *zap.Logger) error {
	if err := validateEventCreationImpact(incData); err != nil {
		return err
	}

	if err := validateEventCreationTimes(incData, logger); err != nil {
		return err
	}

	if len(incData.Updates) != 0 {
		return apiErrors.ErrIncidentUpdatesShouldBeEmpty
	}

	return nil
}

func validateEventCreationImpact(incData IncidentData) error {
	if (incData.Type == event.TypeMaintenance || incData.Type == event.TypeInformation) && *incData.Impact != 0 {
		return apiErrors.ErrIncidentTypeImpactMismatch
	}

	if incData.Type == event.TypeIncident && *incData.Impact == 0 {
		return apiErrors.ErrIncidentTypeImpactMismatch
	}

	return nil
}

func validateEventCreationTimes(incData IncidentData, logger *zap.Logger) error {
	// you can't create an incident with the end_date
	if incData.Type == event.TypeIncident && incData.EndDate != nil {
		return apiErrors.ErrIncidentEndDateShouldBeEmpty
	}

	// you can't create an incident in the future
	if incData.Type == event.TypeIncident && incData.StartDate.After(time.Now().UTC()) { //nolint:revive
		now := time.Now().UTC()
		logger.Debug("start_date validation failed: start_date is in the future",
			zap.Time("start_date", incData.StartDate),
			zap.Time("current_time", now),
			zap.Duration("difference", incData.StartDate.Sub(now)),
		)
		return apiErrors.ErrIncidentStartDateInFuture
	}

	if incData.Type == event.TypeMaintenance && incData.EndDate == nil {
		return apiErrors.ErrMaintenanceEndDateEmpty
	}

	return nil
}