Resolve "follow up visit creation"

Closes #192 (closed)

added 2 commits

• 573dae44 - configuration parameter that determines if study follow up visit should be created automatically
• f4912e35 - notification about subject without visit excludes subject with active vouchers

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unmarked as a Work In Progress

enabled an automatic merge when the pipeline for f4912e35 succeeds

merged

mentioned in commit de93720e