Detecting names in text fields

[MWYang]

SmartTextVectorizer now has an optional flag detectSensitive that will guess, using a combination of dictionary lookup and conditional logic, whether any of the input columns are names (which we don't want in our models in case of bias). For right now, just a warning is logged to console that there may be such names in the input fields. In the future, the removeSensitive flag will remove those columns from contributing to the output vector. Also in the future, the gender information that is extracted from name columns (using government data) will be used to check for model fairness.

A unary estimator HumanNameIdentifier is also included as a standalone drop-in for custom workflows.

Additional context
I completed this work as part of my ongoing Salesforce internship. This PR cleans up and replaces #428.

[codecov]

Codecov Report

Merging #440 into master will decrease coverage by 3.76%.
The diff coverage is 18.62%.

@@            Coverage Diff             @@
##           master     #440      +/-   ##
==========================================
- Coverage   86.93%   83.17%   -3.77%     
==========================================
  Files         337      339       +2     
  Lines       11096    11296     +200     
  Branches      362      597     +235     
==========================================
- Hits         9646     9395     -251     
- Misses       1450     1901     +451

Impacted Files	Coverage Δ
...orce/op/utils/stages/NameIdentificationUtils.scala	0% <0%> (ø)
...scala/com/salesforce/op/utils/text/TextUtils.scala	42.85% <0%> (-57.15%)	⬇️
.../scala/com/salesforce/op/dsl/RichTextFeature.scala	69.44% <0%> (-13.66%)	⬇️
.../scala/com/salesforce/op/features/types/Maps.scala	77.77% <0%> (-15%)	⬇️
...n/scala/com/salesforce/op/testkit/RandomText.scala	98.41% <0%> (-1.59%)	⬇️
...e/op/stages/impl/feature/HumanNameIdentifier.scala	0% <0%> (ø)
...com/salesforce/op/features/FeatureSparkTypes.scala	99.14% <100%> (ø)	⬆️
...sforce/op/features/types/FeatureTypeDefaults.scala	96.15% <100%> (+0.03%)	⬆️
...e/op/stages/impl/feature/SmartTextVectorizer.scala	58.82% <26.92%> (-40.03%)	⬇️
...esforce/op/features/types/FeatureTypeFactory.scala	98.27% <50%> (-0.85%)	⬇️
... and 41 more

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[MWYang]

Closing to rework on comments from reviewers.