Move openfermion functions to correct modules

[soranjh]

Context:
The qchem functions that depend on openfermion and pyscf are all collected in the openfermion_pyscf module.

Description of the Change:

Benefits:

Possible Drawbacks:

Related GitHub Issues:

[github-actions]

Hello. You may have forgotten to update the changelog!
Please edit doc/releases/changelog-dev.md with:

• A one-to-two sentence description of the change. You may include a small working example for new features.
• A link back to this PR.
• Your name (or GitHub username) in the contributors section.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.67%. Comparing base (d90137d) to head (9921079).
Report is 247 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5863      +/-   ##
==========================================
- Coverage   99.68%   99.67%   -0.01%     
==========================================
  Files         421      421              
  Lines       40461    40165     -296     
==========================================
- Hits        40332    40035     -297     
- Misses        129      130       +1     

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[soranjh]

[sc-59835]

[obliviateandsurrender]

Looks good to go! Don't forget to add it to the changelog here.

[ddhawan11]

Looks good.