Change operation IDs to hashed values (aws#150)

Author: nvasiu

sdk/src/main/java/software/amazon/lambda/durable/DurableContext.java

@@ -2,7 +2,6 @@
 // SPDX-License-Identifier: Apache-2.0
 package software.amazon.lambda.durable;
 
-import com.amazonaws.services.lambda.runtime.Context;
 import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
@@ -13,7 +12,11 @@
 import java.util.function.BiConsumer;
 import java.util.function.Function;
 import java.util.function.Supplier;
+
 import org.slf4j.LoggerFactory;
+
+import com.amazonaws.services.lambda.runtime.Context;
+
 import software.amazon.lambda.durable.execution.ExecutionManager;
 import software.amazon.lambda.durable.logging.DurableLogger;
 import software.amazon.lambda.durable.model.OperationSubType;