upload-terminology command - add explicit current version control

[jmarchionatto]

A new optional boolean flag will be added to the CodeSystem uploader, indicating whether the CodeSystem being uploaded is the current version.

• If this flag is present and set to true, the CodeSystem version being uploaded will be marked as the current version, and any CodeSstem queries that do not explicitly indicate a version will use it. Any over versions of the CodeSystem will be marked as not being the current version.
• If this flag is present and set to false, the CodeSystem version being uploaded will not be marked as the current version. If the version being uploaded is already the current version and this flag is set to false, an error will be raised and the operation will be aborted.
• If this flag is missing, the system will treat the upload as if the flag was set to true (preserving the existing behaviour)

HAPI FHIR Version: HAPI FHIR 5.4.1 (Pangolin)