V6.2 D Group Assign Patch

What changed:
- Groups dropdown now refreshes Group Assign board immediately.
- Select 4 Groups to show Group D list/column.
- Every group column has an 'Add team to Group X' dropdown.
- Unassigned teams have quick A/B/C/D/E buttons.
- Group D column is highlighted.

Use:
1. Open Tournament tab.
2. Set Groups = 4 Groups.
3. Group D list appears.
4. Add teams to Group D using the dropdown or D quick button.
5. Save Group Assign.
6. Generate Tournament Fixtures.