Move pfe-base back into main Dockerfile
Move pfe-base back into main Dockerfile

There's finally a binary version of phantomjs, which was the only reason
we separated these before.

fmnhExhibits/Panoptes-Front-End,mrniaboc/Panoptes-Front-End,jelliotartz/Panoptes-Front-End,fmnhExhibits/Panoptes-Front-End,alexbfree/Panoptes-Front-End,amyrebecca/Panoptes-Front-End,alexbfree/Panoptes-Front-End,parrish/Panoptes-Front-End,mrniaboc/Panoptes-Front-End,parrish/Panoptes-Front-End,parrish/Panoptes-Front-End,amyrebecca/Panoptes-Front-End,mrniaboc/Panoptes-Front-End,amyrebecca/Panoptes-Front-End,jelliotartz/Panoptes-Front-End,fmnhExhibits/Panoptes-Front-End,alexbfree/Panoptes-Front-End,zooniverse/Panoptes-Front-End,jelliotartz/Panoptes-Front-End