Add a Java and Python example (HTTP + CloudEvent) for no reply functions

[andrew-su]

Feature Request

Add a Python and Java example (HTTP + CloudEvent) where the function does not return a reply.

This covers scenarios where the function takes a long time to process the work so it just accepts it or queues it.

Acceptance

An example function for Java that doesn't reply but still processes the requests correctly.
An example function for Python that doesn't reply but still processes the requests correctly.

[bbtong]

This development work went stale, but progress can be found at fabl/no-reply-java-sample.