Fix requirements.txt

[spacemansteve]

Upgraded celery to from 4.1.0 to 4.1.1. Specify a compatible version of kombu.

Remove libraries from pipeline requirements.txt files that duplicate libraries in ADSPipelineUtils. For example, ADSPipelineUtils duplicates the following libraries already specified in ADSPipelineUtils: celery, ConcurrentLogHandler, DateTime, python-dateutil, SQLAlchemy.

[marblestation]

Merged PR #25 fixes the celery requirement.