Address Dependency of FeatureBuilder on having "chat" or "turn" in the input path name.

[xehu]

Currently, the FeatureBuilder (feature_builder.py) assumes that we are passing in an output file path that contains either "chat" or "turn" in the name, as it saves the featurized content into either a "chat" folder or "turn" folder based on user
specifications.

Relevant code:

        self.output_file_path_chat_level = re.sub('chat', 'turn', output_file_path_chat_level) if self.turns else output_file_path_chat_level
        base_file_name = self.output_file_path_chat_level.split("/")[-1]
        self.vect_path = vector_directory + "sentence/" + ("turns" if self.turns else "chats") + "/" + base_file_name
        self.bert_path = vector_directory + "sentiment/" + ("turns" if self.turns else "chats") + "/" + base_file_name

We should think carefully about this design decision. Can we make the FeatureBuilder robust to output paths that do not have this in the path name? Or, if we absolutely require the output path to have the right keywords in it, can we add error checking and documentation so that when we fail, we fail noisily?