Estimators and their catalog extensions should have matching names

[artidoro]

In #2827, one of the items is to make sure the estimators and their catalog extensions have matching names. Like in trainers, we should keep the suffix estimator only in the estimator name, and remove it from the catalog extension, something like the following:

NameEstimator Name(...)

The question now is: How do we reconcile the names and which convention should we follow?

Most estimator names follow the convention: ActionPerformingEstimator, while in the catalog usually we use the convetion: PerformAction.

Some examples are:

Estimator Name	Catalog Name
KeyToBinaryVectorMappingEstimator	MapKeyToBinaryVector
MutualInformationFeatureSelectingEstimator	SelectFeaturesBasedOnMutualInformation
CountFeatureSelectingEstimator	SelectFeaturesBasedOnCount
...	...

cc/ @sfilipi @TomFinley @glebuk @eerhardt @rogancarr @ivanbasov

[artidoro]

As per offline discussion, we have concluded that the difference is voluntary. The example given was:

So if I have a class called "CarrotEater", but I have a method that applies it, I'd be surprised if it wasn't named "EatCarrots".