Generate redacted version pluggable logic

As a Studio developer, I can plug custom logic for the "generate redacted version" action.

AC
Default logic is provided out of the box. It does the following:

- Context.PushBlob
- Repository.GetDocument:
    value: "@{ChainParameters[\"originalDoc\"]}"
- Document.Copy:
    target: "@{Document.parent.path}"
    name: "redacted-@{Document.id}"
- Document.SetProperty:
    xpath: "dc:title"
    save: "false"
    value: "@{Document.title} - Redacted"
- Context.SetInputAsVar:
    name: redactedDoc
- Context.PopBlob
- Blob.AttachOnDocument:
    document: "@{Context[\"redactedDoc\"]}"
    save: "true"
    xpath: "file:content"

Logic is executed as an automation chain

Chain is named "ArenderRedactCompletion"

The following information is provided in the context of the chain:

• Redacted blob (input)
• Document where the redaction happened (chain parameter named "originalDoc")
• Number of redactions in the original document (chain parameter named "nbRedactions")

I can override this chain using Nuxeo Studio configuration