cleanup

I made a 'jgitUserInfo' Spring bean to let Spring manage instantiation and properties, but a potentially breaking change is adding the setter to inject the config. Using Holders should typically be a last resort if there's no better approach, but I think it makes sense to set the config once and refer to that rather than repeatedly pulling from Holders.

Also note that UserInfoHandlerTests doesn't really test anything - if you replace UserInfoHandler with ArrayList or any other class with a default constructor it will continue to pass, since you're really testing that adding and calling metaclass methods works.