Add Gaussian harness

[QuChem]

Description

This is the implementation of Gaussian software into QCEngine

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 191 lines in your changes missing coverage. Please review.

Project coverage is 78.18%. Comparing base (1b27a14) to head (aad52cf). Report is 7 commits behind head on master.

:exclamation: Current head aad52cf differs from pull request most recent head a2ff5c8

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Additional details and impacted files

[bennybp]

I think programs.py should be base.py inside the programs folder. You should modify that file with your changes