Single atom fix

[espottesmith]

Production build died because the single_atom.json file was not included in the package version of emmet. To avoid that in the laziest way possible, I've just put all of the data included in that JSON in a dictionary.

[codecov-commenter]

Codecov Report

Merging #413 (3adbddf) into main (6a527eb) will not change coverage.
The diff coverage is 66.66%.

@@           Coverage Diff           @@
##             main     #413   +/-   ##
=======================================
  Coverage   98.08%   98.08%           
=======================================
  Files         109      109           
  Lines       23194    23194           
=======================================
  Hits        22749    22749           
  Misses        445      445           

Impacted Files	Coverage Δ
emmet-builders/emmet/builders/materials/chemenv.py	100.00% <ø> (ø)
emmet-builders/emmet/builders/qchem/molecules.py	96.55% <0.00%> (ø)
...mmet-builders/emmet/builders/molecules/orbitals.py	98.82% <100.00%> (ø)
emmet-builders/emmet/builders/molecules/thermo.py	96.93% <100.00%> (ø)

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