pkg_resources related fixes

[mauvais2]

• Removed the references of pkg_resources
• Deleted top level of init.py
• Updated setup.py

Tests:

• Made sure the ci jobs run fine.
• Created cpu env, build atomsci packages. Ran unit tests and a few integrative tests on LC to verify.

[paulsonak]

these changes look good to me

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

@@             Coverage Diff             @@
##            1.8.0     #427       +/-   ##
===========================================
+ Coverage   40.57%   51.41%   +10.84%     
===========================================
  Files          49       36       -13     
  Lines       13537    10685     -2852     
===========================================
+ Hits         5493     5494        +1     
+ Misses       8044     5191     -2853     

Flag	Coverage Δ
unittests	51.41% <ø> (+10.84%)	⬆️

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see 14 files with indirect coverage changes

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