Introduce a working pattern history for EE's with effective date / week # specification capabilities

Currently, working patterns that are comprised of more than a single work week (for example where week 1 is Mon - Fri but Week 2 is Mon - Thur) work based on the pattern effective date, which can default back as far as 01/01/1990.

As the work pattern is used in items like SMP scheduling, this means that the pattern can end up with Week 1 applied where Week 2 is expected, which can lead to confusion in the number of 'working days' the employee is calculated on in a period.

To make this easier, I would propose that we have a 'Working Pattern History', where it's possible to assign 'effective dates' for working patterns to an employee, including which week # in the working pattern should be used first from that date (rotating from that week number -> highest then repeat from week #1 going forward).

This would better serve the ability to see the impact of a working pattern (especially where the pattern is comprised of a multiple week rotation) so that any relevant corrections can be made and impact upon items like SMP schedules can be easily evaluated and corrected where required.