Add function to perform just the transformation

[hammadk373]

Currently the converter only works when converting the contents of the CSV to FHIR resources. The dataframe transformation/normalization logic is very powerful and useful on its own. We would benefit from utilizing this transformation logic to convert to other arbitrary data models.

[klwhaley]

Reopening until we cut a full release with this in it.

[klwhaley]

Included in release 1.1.0 https://github.com/LinuxForHealth/CsvToFHIR/releases/tag/1.1.0