Creating an example feature extractor for use in documentation to sho…

[drewoldag]

Created an example feature extractor for use in documentation to show people who to develop external FE libraries.

The goal was to implement as little as possible but still portray the methods, class methods, and attributes that need to be implemented.

[github-actions]

Before [cd86501]	After [eb0225e]	Ratio	Benchmark (Parameter)
3.00±0s	3.07±0.02s	1.02	benchmarks.time_learn_loop('RandomForest', 'UncSampling')
195M	197M	1.01	benchmarks.peakmem_learn_loop('KNN')
3.02±0.01s	3.05±0.01s	1.01	benchmarks.time_learn_loop('RandomForest', 'RandomSampling')
194M	194M	1	benchmarks.peakmem_learn_loop('RandomForest')
164±3ms	163±0.8ms	1	benchmarks.time_learn_loop('KNN', 'UncSampling')
160±1ms	158±2ms	0.99	benchmarks.time_learn_loop('KNN', 'RandomSampling')
137±0.9ms	134±1ms	0.98	benchmarks.time_feature_creation

Click here to view all benchmarks.