Support freezing Hartree-Fock energies at each forging iteration

[caleb-johnson]

This PR allows users to set the HF energy explicitly, rather than calculating it at each iteration with quantum experiments. This can improve the runtime of the algorithm, and it can also improve results.

• Make release note
• Link to explanatory in docstring
• Change variable names in knitter to reflect that the hf_energy has been shifted
• Get new code up to 100% coverage

[coveralls]

Pull Request Test Coverage Report for Build 5615729580

• 34 of 34 (100.0%) changed or added relevant lines in 2 files are covered.
• 3 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.8%) to 90.823%

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Files with Coverage Reduction	New Missed Lines	%
circuit_knitting/forging/entanglement_forging_operator.py	1	59.09%
circuit_knitting/utils/orbital_reduction.py	2	60.0%

Totals
Change from base Build 5433896893:	0.8%
Covered Lines:	2593
Relevant Lines:	2855

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💛 - Coveralls

[garrison]

This looks basically good, I just marked a few things that were not entirely clear to me. 🙂