Complex iterative review and approval workflows

[anvabr]

Problem description

Real world document review and approval processes are often nuanced and complex, with multiple iterations of exchanging comments, questions, change requests, other forms of feedback, and then corrections and resubmissions. Furthermore these processes can be of varying length - i.e. they can last from hours to several months or even years. At present Guardian workflow does not 'natively' support this - policy authors have to implement such cycles in every policy and at policy run time project participants would have to rely on limited communication capabilities ('reason for approval').

See also: #3681, #2845, #3617

Requirements

Introduce reviewVcDocumentBlock as a complement to the requestVcDocumentBlock into Policy definition language and corresponding Guardian UI tools which would facilitate complex iterative document review workflows supporting rich communications, namely the ability to:

• send messages/descriptions associated with actions
• conduct stand-alone (not action-linked) message exchanges (questions, responses, general comms)
• send requests for providing additional documents/evidence, and provide facilities to upload/receive them
• ability to edit/correct previously submitted (but rejected) document and resubmit again
• forward messages to another user
• involve other users into 'conversations'

These actions, steps, message exchanges have to be verifiably traceable, i.e. recorded and published as VC/VP documents alongside the usual data-containing documents produce by the policy workflows.

Definition of done

• Functionality is implemented per requirements above
• Documentation is provided
• At least a single example of the usage of this functionality is implemented in any of the policies in the Guardian repository

Acceptance criteria

Policy authors can introduce complex approval workflows into the policy which enable users to interact during approval process