Improves jira release lookup

[fkrauthan]

This is to improve the lookup for existing releases:

1. It checks if a release exists (while using the filtered API endpoint to only load releases with the version as name)
2. Only lookup project id if the release needs to be created
3. Only create the release if the release was not found

I also haven't tested it but I am pretty sure that updating releases does not really work as the createVersion call of jira-client throws an exception if errorMessages are populated.