Bugfixes in jury capacity change

* old seats up to the new capacity are preserved
* optimal load is calculated correctly even after the solution is cloned
* jury capacity change allowed in UI
Drop redundant field Jury.capacity
Jury capacity: minor UI fixes

* change GroupRoster preferred size if capacity changes
* disable juryCapacitySpinner until a schedule is loaded
Don't disable save action after clearing the schedule
Better display of empty seats

* fixed row width
* always show the leading icon
Update score after changing jury capacity