Adding an ability to use a default implementation for sending history.

[dmitrii-beliakov]

I extracted interfaces from AbstractBolt, this allows to have an interface with the default implementation for sending history. I chose it to be an interface and not a class in the hierarchy of bolts, so that we can opt-in or opt-out the default implementation more easily. Also it was needed to move classes to another module, up in the dependency structure.
I added the usage to one bolt to show how it is going to look like.

Although is solves code duplication problem, there are some downsides:

• this interface cannot enforce a topology to declare what is needed to be declared.
• the access modifiers for some methods changed to be public (I actually don't know why and don't really see the need for it, the class that extends one of the abstract bolts is not inherited and used only in topologies. This is not super clear point. Bolts could be final to resolve this).
• there is a need to unify the naming of streams and bolts for history.

[IvanChupin]

Great job! The approach to move save history methods into one separate interface looks really convenient.

[IvanChupin]

Just out of curiosity, you decided to point out explicitly AccessLevel.PUBLIC only to keep the common behaviour here, like as it is in the cases for AccessLevel.PROTECTED?

[dmitrii-beliakov]

It is a part of an interface now, so it has to be public

[IvanChupin]

Would it be more convenient to keep HUB_TO_HISTORY_TOPOLOGY_SENDER constant in the Stream enum?

[dmitrii-beliakov]

Yes, I have a thought that it needs to be in some place that is accessible in the bolts and the service at the same time. We need this constant when configuring topologies, so it would be convenient to have some unified approach of adding. If it is a helper method then it can't be enum that we have in the topology package.
This is a task to think about. But once it is done, we can change this method without changing the rest of the code.

[niksv]

I think getHistoryStreamName() must be used in declareOutputFields