[WIP] PUBDEV-6671: Add `feature_frequencies` to Performance and Prediction section (#3714)
[WIP] PUBDEV-6671: Add `feature_frequencies` to Performance and Prediction section (#3714)

* PUBDEV-6671

Added a topic after Prediction Threshold called Predict Feature Frequency.

* Update for feature_frequencies examples

* Fixed feature_frequencies example

* Further updates (added example output, minor edits)

h2oai/h2o-3,michalkurka/h2o-3,michalkurka/h2o-3,michalkurka/h2o-3,h2oai/h2o-3,h2oai/h2o-3,h2oai/h2o-3,h2oai/h2o-3,michalkurka/h2o-3,h2oai/h2o-3,h2oai/h2o-3,michalkurka/h2o-3,h2oai/h2o-3,michalkurka/h2o-3,michalkurka/h2o-3