Adding workflow durability by allowing persistence between each stage

[cortexteam]

Adding an optional callback which can be used to persist the message state at each workflow stage to allow long-running workflows to become durable and resumable.

[agebert]

@cyrilschmitt what do you think about this enhancement?

[cyrilschmitt]

Hello cortexteam,

Thank you for contributing, the ideas are valid but I have some remarks before merging this.

I would like it in multiple commits because I think there are different unrelated changes:

• getNumberOfProcesses
• delete and _autoCleanFinishedProcess (these are related so OK for both in one commit)
• persist and resumeProcess (also related so one commit)

I think resumeProcess should also take processName parameter because in case the manager have multiple processDefinitions then this can be wrong:
Object.keys(self._processDefinitions)[0]
It would alsways use the first definition so replace by processName parameter.

Regards,
Cyril