The Directorate of Posts on Wednesday released a Tk 40 souvenir sheet, an envelope of Tk 10, a Tk 5 data card and a special seal stamp marking the Constitution Day of Bangladesh.   Posts, Telecommunications and Information Technology Minister Mustafa Jabbar inaugurated them from his office.   On November 4, 1972, Bangladesh adopted its Constitution and it was effective from December 16 that year.   It provided the framework of the Bangladeshi republic with a parliamentary government, fundamental human rights and freedoms, an independent judiciary, a democratic local government and a national bureaucracy.