store/editing_store library

1. editable_chess_board package
2. documentation
3. store/editing_store.dart

editable_chess_board package

1. Libraries
2. advanced_options
3. board
4. board_color
5. editable_chess_board
6. piece
7. piece_type
8. rich_chess_board
9. selection_zone
10. square
11. store/editing_store
12. ui_piece
13. ui_square
14. ui_tile
15. utils