Add qchem basis rotation function

[soranjh]

Context: This PR adds a function for basis rotation grouping of a molecular Hamiltonian.

Description of the Change: The function basis_rotation is added to qchem.factorization module.

Benefits:

Possible Drawbacks:

Related GitHub Issues:

[github-actions[bot]]

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[codecov[bot]]

Codecov Report

Merging #3011 (a09184b) into master (6d8ae8f) will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #3011   +/-   ##
=======================================
  Coverage   99.68%   99.68%           
=======================================
  Files         273      273           
  Lines       23605    23632   +27     
=======================================
+ Hits        23531    23558   +27     
  Misses         74       74           

Impacted Files	Coverage Δ
pennylane/qchem/__init__.py	100.00% <100.00%> (ø)
pennylane/qchem/factorization.py	100.00% <100.00%> (ø)

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