Create ontology for ICDCoding

[Piyush13y]

Is your feature request related to a problem? Please describe.
According to #14, we should be defining the ontologies that will be required for this processor. A new parent ontology has to be defined under forte.data.ontology.top.Generics. MedicalArticle would be the parent ontology which would represent the whole text of a discharge note, etc. ICDCode - child ontology name and there will be couple of attributes within this, namely code (as string) and version (int). These can then be used to store coding information as such:
example input: "Patient has been diagnosed with lung tuberculosis"
example output ontology:

- MedicalArticle
  - ICDCode
      - code "A15.0"
      - version 10