GTNPORTAL-3506 Allow multiple apps registering the very same AMD paths

+1 JavaDoc changed:
```
         * Copies this into a new {@link StaticScriptResources} instance, removes all entries
         * with the given {@code contextPath} from {@link #entries} of the new instance and returns
         * the new instance. Returns {@code this} if there is nothing to change.
         *
         * @param contextPath a servlet context path
         * @return
```