Programmatic extension of regexes in order to detect custom terms which are not defined in yaml

[mdesalvo]

Is your feature request related to a problem? Please describe.
In the context of a conversational chatbot, I need to declare custom terms for Italian choice recognition which are not included in the built-in yaml (e.g: "ottimo", "perfetto", "giusto", "esatto", "corretto", "esattamente" would all give the boolean true).
So at the moment I cannot detect these responses from the user.

Describe the solution you'd like
I would like to have a programmatic way to expand the built-in regexes of a specific recognizer, in order to detect custom terms without rebuilding the library from source or without waiting for someone to commit new terms. It may help having a friendly helper exposing customization APIs like "ChoiceRecognizer.AddCustomTerm('ottimo', 'it-it', 'TrueRegex')".