example: Aggregate with init

[sehz]

Add example of SmartModule with aggegrate that can be used in the chaining. Existing Aggegrate example only can be used in the "classic" SmartModule with argument --smartmodule. We need example that works with --transforms-file.

[ajhunyady]

For this issue to solve #3120 , we need the ability to read the last record from the stream in the init call.

[sehz]

For this issue to solve #3120 , we need the ability to read the last record from the stream in the init call.

That will be handled in the new issue. This issue is limited in scope.