Reduce number of nodes on Serverless Workflow process definition

[fjtirado]

Description

Serverless Workflow parser is reusing jbpm nodes that were defined for bpmn standard.
When there is not direct mapping, as it happen with data filters and several function types, we are relying on a mix of multiple composite, action and workitem nodes.
The purpose of this issue is to explore the possibility of adding additional nodes to the engine the are better suited for those purposes.
With that we will achieve:

1. Smaller process definitions
2. Faster execution performance
3. Easier mapping between nodes and states in runtime tooling
4. The possibility of generating a workflow from a process definition.

Implementation ideas

Add SWFStateNode and SWFStateNodeImpl for data filtering purposes.
The connection link, switch state, compesation and error handling will still rely on the engine as they are now.
Start with Operation and ForEach states.