JAL-3789 Use j2s.config.altfileproperty in .j2s for alternative temporary build/jalviewjs/config/j2s settings file when running a headless build in gradle
JAL-3594 Allow setting of getdownappbase and getdowndistdir properties for DEVELOP channel, and change DEVELOP version to be VERSION-dDATE instead of VERSION-develop. dDATE will help users know when Jalview Develop applicaiton updated