Add compute_drug_likeness function to rdkit_easy

[mcloughlin2]

Add a function to the rdkit_easy module to compute various drug-likeness criteria for compounds in a data frame (Lipinski rule of 5, Ghose and Veber filters, QED), along with the descriptors used to derive them.

[codecov]

Codecov Report

Attention: Patch coverage is 82.08955% with 12 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
atomsci/ddm/utils/rdkit_easy.py	82.08%	12 Missing ⚠️

@@            Coverage Diff             @@
##            1.7.0     #384      +/-   ##
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+ Coverage   20.29%   23.35%   +3.06%     
==========================================
  Files          47       47              
  Lines       12883    12950      +67     
==========================================
+ Hits         2615     3025     +410     
+ Misses      10268     9925     -343     

Files with missing lines	Coverage Δ
atomsci/ddm/utils/rdkit_easy.py	42.70% <82.08%> (+42.70%)	⬆️

... and 5 files with indirect coverage changes