Add victory sequences and prepare for side-vs.-team rework.
NGCGame: rename side to player_side; only record time control against player's side; if black, delay first move until after announcements; play victory sequences.
NGCFireworks: new script providing a fireworks display for victory sequences.
NGCPiece: add celebration motion; remove get_heraldry_source (using attenuation factors instead); face the enemy at the beginning of a reposition too.
NGCScenario: replace chess_set_white and _black with chess_set again; close the wall even quicker.
NGCClock: remove side parameter.