Calendar Template Update

not all public holidays are on the same date annually. Two Exmaples: Thanksgiving Day - Fourth Thursday in November and Memorial Day - Last Monday in May

it would be ideal to add extended capabilities in setting calendar templates to accommodate for this. to be able to set "occurs annually, fourth thursday in november"

this way the national recurring holidays will never have to be changed. right now, since only a specific date can be set, then customers will have to adjust annually. I'm not sure how this impacts the project details too with a multi-year project