Architecture - Phase 1 - Creating room

[grovesy]

Create room for change, without changing behavior

• Introduce a WorkflowContext object, passed through all chain processors
• Standardize a HandlerResult envelope
• Add correlation IDs / Actions IDs consistently to logs, db entries etc.
• Add a startup validator for config/registered handlers
• Create a 'shim' between old handler signatures and new - for any externally written handlers

Non-breaking rule

• no config changes.
• Existing chain order remains preseved and source of truth
• This is internal refactoring's only

*Grovesy working on this issue, will @ when ready