fixed typo. 'dashboard'

This is primarily related to Cloud Events. Since we delegate to a separate class for post processing, if outpt message is Cloud Event we will not be doing anything to with regard to header copy in SimpleFunctionRegistry and unstead delegate it to CloudEventFunctionInvocationHelper

Also, restructured CloudEventsFunctionInvocationHelper's postProcessig logic

Added reactive tests
Restructured CloudEventsFunctionInvocationHelper

Fix deserializatioin error when using complex signatures such as Function<Tuple2<Flux<Message<String>>
The issue originated from spring cloud stream https://github.com/spring-cloud/spring-cloud-stream/issues/2065

Add FunctionInspector dependency back to SimpleFunctionRegistry since we can't remove it yet to avoid backward comatibility issues

Resolves #617

Resolves #618

Ensured Cloud Event completness by adding assertion for required attributes as well as generation of default values for attributes such as ID and SPECVERSION

Added initial test to validate builder and utils

This reverts commit 1925b490.

There was a TODO in the cloud events section of the function catalog.
This extracts that into a strategy and autoconfigures it:
CloudEventOutputMessageHeaderEnricher.

Without this change a function with a Tomcat wrapper cannot be compiled
to a native image (or it can but it fails at runtime) because there
are lambda$$$ methods in the byte code that refer to missing types.

Resolves #611