Create a ClassLoaderService to abstract away dealing with the default ClassLoader directly

With the addition of ClassLoader isolation using JBoss Modules GEODE-8067, the manner in which we interact with the ClassLoader needs to change.

An abstraction is required around the default functions like `findResourceAsStream`, `loadClass` and `loadService`.

As these features will behave differently between different ClassLoader implementations, it is best to have a single service that will expose that functionality in a transparent manner.