Replacing Advice.class references with string construction.
This stops the JVM from loading the Advice classes which are used as templates for byte buddy and doesn't ever need to be run directly.
This eliminates ~130 class loads at start-up -- and saves 0.5MiB in metaspace
For spring:
* Move more logic to the decorator.
* Use a fixed operation name, but set the resource name.
* Rename the root span instead of the parent span (If there are other spans in between this could make a difference.) Not sure what impact this would have if multiple controllers are called (ie, forward/include).
For Jax-rs:
* Rename the root span instead of the parent span (same concern as above with spring)