Add actor closure implementation on Java

[kol-oss]

• Rewrite JavaScript global function with closure (createActor) as Java static factory method (ActorClosureFactory.createActor);
• Implement object instantiation and method calls via Java Reflection API;
• Create Actor interface to represent return result with functions send and process;
• Create Operation record to represent set of params to call specified method and pass the result;
• Replace JavaScript Promises with Java CompletableFutures.