sick note security: only office should have access

refs #14631
security: set always-use-default-target to false

refs #14631
personal overview, prepare for showing sick notes

* moved overview stuff out of PersonController in
  PersonalOverviewController
* added UsedDaysOverview object

refs #14631
overview, more details for used vacation days

refs #14640
overview, added sick note list

refs #14631
adjusted nav bar, dropdowns

refs #8755