Match feature type map hierarchy with regular feature types

[tovbinm]

Related issues
Currently it's not possible to restrict stage types by only numeric maps or only by real maps.

Describe the proposed solution
Update feature type map hierarchy to match the regular feature types hierarchy.
This change allows us restrict stage types by only numeric maps for instance:

// This transformer would allow RealMap, IntegralMap, DateMap etc.
class NumericMapVectorizer[I <: OpMap[_] with NumericMap] extends SequenceTransformer[I, OPVector]

// This transformer would allow RealMap, CurrencyMap and PercentMap only
class NumericMapVectorizer[I <: RealMap] extends SequenceTransformer[I, OPVector]

Additional changes:

• MultiPickListMap now extends MultiResponse
• BinaryMap and PickListMap now extend SingleResponse
• Added NumericMap trait with toDoubleMap: Map[String, Double] (to match the OPNumeric with toDouble: Option[Double])

Describe alternatives you've considered
None.

Additional context
We should have done it from day one.

[codecov]

Codecov Report

Merging #49 into master will decrease coverage by 0.9%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #49      +/-   ##
==========================================
- Coverage   85.74%   84.84%   -0.91%     
==========================================
  Files         298      298              
  Lines        9753     9760       +7     
  Branches      329      328       -1     
==========================================
- Hits         8363     8281      -82     
- Misses       1390     1479      +89

Impacted Files	Coverage Δ
...scala/com/salesforce/op/features/types/OPMap.scala	100% <ø> (ø)	⬆️
.../scala/com/salesforce/op/features/types/Maps.scala	92.4% <100%> (+0.29%)	⬆️
...ala/com/salesforce/op/features/types/package.scala	52.98% <100%> (+6.06%)	⬆️
...scala/com/salesforce/op/utils/text/TextUtils.scala	0% <0%> (-100%)	⬇️
.../com/salesforce/op/utils/version/VersionInfo.scala	0% <0%> (-100%)	⬇️
...ala/com/salesforce/op/utils/tuples/RichTuple.scala	0% <0%> (-100%)	⬇️
...scala/com/salesforce/op/utils/numeric/Number.scala	0% <0%> (-100%)	⬇️
...om/salesforce/op/utils/spark/OpSparkListener.scala	0% <0%> (-98.71%)	⬇️
...a/com/salesforce/op/utils/date/DateTimeUtils.scala	95.65% <0%> (-4.35%)	⬇️
...es/src/main/scala/com/salesforce/op/OpParams.scala	85.41% <0%> (-4.17%)	⬇️
... and 1 more

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