Take Netty 4.0.35 bundled epoll into account

Since Netty 4.0.35, the native epoll library comes bundled with the artifact, and a property can be used to indicate that Netty is shaded.

So we should set up the system property to indicate to Netty that its classes have been shaded and relocated, and also modifies the pom so that Netty newly integrated epoll native
library is integrated in the shaded jar as a renamed/relocated version.