When a merge request can only be merged when all discussions are resolved. This feature allows to easily delegate those discussions to a new issue, while marking them as resolved in the merge request. The user is presented with a new issue, prepared with mentions of all unresolved discussions, including the first unresolved note of the discussion, time and link to the note. When the issue is created, the discussions in the merge request will get a system note directing the user to the newly created issue.
The implicit interface of project services states that the "execute" method is meant to be called when project hooks are executed. Currently JiraService does not support any project events even though JiraService#supported_events says that "commit" and "merge_request" are supported. They are only used to render correct options in JIRA configuration screen, but they are not supported. Because of that, this commit makes "execute" method a no-op.
This moves the code used for processing commits from GitPushService to its own Sidekiq worker: ProcessCommitWorker. Using a Sidekiq worker allows us to process multiple commits in parallel. This in turn will lead to issues being closed faster and cross references being created faster. Furthermore by isolating this code into a separate class it's easier to test and maintain the code. The new worker also ensures it can efficiently check which issues can be closed, without having to run numerous SQL queries for every issue.