Make queueName and topicName as not required in ServiceBus outbinding…

[james-damstra]

…. Otherwise generated functions.json will include topicName and queueName with default value.

What did you implement:

Closes #352

How did you implement it:

The service bus binding need either queueName or topicName

How can we verify it:

I link it to my project which use service bus out binding with topic and did a sls deploy. Verify the function.json only contain topicName instead of both topicName and queueName attribute.

Todos:

Need the ability to require either attribute. Basically we need the ability to specify topicName or queueName is required.

Is this ready for review?: YES Is it a breaking change?: NO