Added new commands to reproschema

[Evan8456]

• Added command reproschema-ui-to-redcap command to convert the the exported results from reproschema-ui into a redcap csv file
• Added command reproschema-to-fhir to convert Reproschema into FHIR Questionnaire resources.
• Added tests scripts for both commands.

[yibeichan]

@Evan8456 thank you! Can you

• add examples of converted fhir and redcap output somewhere, maybe create a folder called example?
• add some documentation to explain how to use those two command?

[Evan8456]

@yibeichan Added examples and documentation.

[yibeichan]

@Evan8456 thank you! can you

• add one short paragraph of the description each under reproschema-ui-to-redcap and reproschema-to-fhir about what those functions are for. For example, reproschema-ui-to-redcap converts reproschema output to redcap csv format. and then give a pointer to reproschema output and redcap csv. that's why I asked for examples.
• change reproschema-ui-to-redcap to output2redcap
• change reproschema-to-fhir to reproschema2fhir

make sure changes of command names are consistent every where, including main function names.