Make it possible to re-create missing SourceChange events This change add the flag fillGaps for the createSccs and createScss endpoints. With this flag you can re-create missing events. Traversing from the root of the commit tree every missing event is re-created until the specified commit or tip of the specified branch is reached. Solves: Jira GER-1545 Change-Id: I2c3d5067c0e080b04c8890ceff18b4f6534ec274