API change to add study ID to the health code table
Merge pull request #379 from eric-wu/update

Stop writing consent signature to DynamoDB
Implement the study ID column
Remove logging
Add a new table for the new study ID column
Make the study ID field public
Remove version 2 of the table as it is not needed.
Remove the constructor that only takes the health code.
Remove the invalid import
Merge pull request #380 from eric-wu/develop

Add study id to the health code table
Fix Travis test failures
Remove Jasypt password
Add back the needed Travis env variable
Remove Jasypt password