Java support

[yojagad]

Part of work for #60

@jeffhollan / @fabiocav Following the signalr way of adding annotations for an extension (https://github.com/Azure/azure-functions-signalrservice-extension/tree/master/binding-library/java)

cc: @cachai2

Below is an example java function

/**
 * Azure Functions with HTTP Trigger.
 */
public class Function {
    @FunctionName("RabbitMQExample")
    public void run(
            @RabbitMQTrigger(
                connectionStringSetting = "ConnectionString",
                queueName = "TestQueue"
            ) String input,
            @RabbitMQOutput(
                connectionStringSetting = "ConnectionString",
                queueName = "hello"
            ) OutputBinding<String> output,
            final ExecutionContext context) {
        context.getLogger().info("Java HTTP trigger processed a request." + input);
        output.setValue(input);
    }
}

[fabiocav]

Thanks! Would be good to get @pragnagopa 's feedback here, as I know this differs from the initial proposed implementation

[pragnagopa]

@jeffhollan / @fabiocav - I recommend following similar approach as signalr and create Java annotations in this repo.

This allows keeping annotations and c# attributes in sync and can be released independently of azure-function-java-library

[pragnagopa]

Added minor comments

• Open issue to add integration test that verifies function.json generated by mvn
• Update PR description with same java function that uses this annotation. Later can be re-used in the documentation

[yojagad]

@pragnagopa Added issue here #112

[pragnagopa]

Added few more nits . Thanks

[pragnagopa]

Approved. Nit, fix format before merging.