The wacky wigmaker who wantonly mowed down a Brooklyn mom and her two young daughters scored a sweetheart plea deal over the objections of prosecutors. Miriam Yarimi, 33, pleaded guilty last month to manslaughter after Judge Danny Chen offered a 3-to-9-year sentence, records show. The deal was far less than the 15-year maximum sentence sought by Brooklyn prosecutors, who plan to submit a letter ahead of her Wednesday sentencing detailing the many reasons they contend Yarimi should be locked up