On the eve of Joel Steinberg's parole from prison, the foreman of the jury that put him behind bars thinks the cold-hearted child killer should rot there until his 25 years are up. "It was a truly reprehensible thing he did, and the penalty he's thus paid is not sufficient," ex-juror Jeremiah Cole told the Daily News yesterday. "The judge in the case recommended he serve the full sentence and I thought, under the circumstances, that was an excellent recommendation." Steinberg, 63, will be freed tomorrow from the Southport Correctional Facility in upstate Chemung County after serving the required two-thirds...