Support synchronization of a single Build

I added a story to handle the case where the build number is not provided or in the case its the hourly sync operation, see JJI-487.

That would be great We have disabled the hourly synchronization, so just rely on the build completed notification - this presumably contains the build number, so it would be nice if just that build was synchronized, especially for projects with hundreds of builds

I have not fully flushed out the design for this, but my thinking is to handle synchronization in the following ways.

1. in case the Jenkins add-on notifies of a build completion

   1. if the notification contains a build number, the only synchronize this build

   2. otherwise, keep with current behaviour and synchronize all builds, new and old.

2. in case of hourly synchronization, behaviour should be unchanged and continue to synchronize all builds available on Jenkins

I'm also thinking of a better way to handle builds that have been synchronized already, but have not yet found a way for this.

Will this resolve the current behaviour, where the plugin re-requests build data for every build in a project when a single build completes (even those that it already knows about)?