Hi Alexander,
You're getting yourself confused between the context path, and the servlet path.
The context path is the path at which the webapp is deployed, such as "/" or "/xyz". Servlets are then deployed at paths relative to that context path. A request is matched first against the context paths of the webapps deployed to find the 'best' (ie as defined by the servlet spec) match, and then against the servlets deployed within the selected webapp for the 'best' match.
A webapp can only have a single context path, so your config file is wrong there: choose either "/" or "/hello" but not both. So if you choose "/" as the context path, and you have a servlet mapped to "/hello/*", then the url
http://localhost:8080/hello will route to that servlet. If instead you chose the context path "/hello" and still have a servlet mapped at "/hello/*", then you would need to hit the url
http://localhost:8080/hello/hello to route to it.
Also, the difference between the jetty maven plugin and the deployer from the distribution if you don't provide an explicit context path is: the jetty maven plugin chooses a context path that is the artifactId prefixed with '/', whilst the deployer chooses the filename of the war (minus any file extension) prefixed by '/'.