Support specifying clinicalSiteSystem in configuration file

[dmendelowitz]

Summary

clinicalSiteSystem can now be specified in the config file, similar to how clinicalSiteID is, except clinicalSiteSystem is optional

New behavior

If a clinicalSiteSystem is added to the constructorArgs of CSVClinicalTrialInformationExtractor in the config file, that value will be used for the system field of the site object in the ResearchStudy resource. If no system is specified, the system field will be omitted in the output.

Code changes

• CSVClinicalTrialInformationExtractor.js now takes an optional clinicalSiteSystem constructor argument and adds that to the formatted data for the Research Study
• ResearchStudyTemplate.js now takes an input for clinicalSiteSystem instead of just using an example.com value
• CSVClinicalTrialInformationExtractor.test.js and researchStudy.test.js have been updated to reflect the above changes

Testing guidance

• Add a value for clinicalSiteSystem to the constructor arguments of the CSVClinicalTrialInformationExtractor and see that the correct value appears in the output and that there is no system in the output if the argument is removed from the config
• Make sure the new tests pass and accurately test the new functionality

[julianxcarter]

Looks good to me!