Expand the cookie JAR across workflows

[forgedhallpass]

Scenario: create a workflow that starts with a template that logs in to an application, and then all the subsequent templates would automatically contain the session cookies.

[Mzack9999]

General implementation notes:

• The workflow should instantiate a cookie jar instance before starting the execution
• The templates part of the workflow should be provided with the shared cookie jar that the respective retryablehttp client will use
• Templates within a workflow involving a cookie jar should probably not be clustered to avoid leaking cookies to other execution contexts
• It might be necessary to introduce conditional flow/execution order: for example, executing the login template, checking on its results, and then proceeding with further exploitation

[forgedhallpass]

Options to consider:

• Global scenario:

cookie-reuse: true # all templates within this workflow can read and modify cookies
workflows:
  - template: a.yaml # e.g. this templates creates a JWT with a timestamp
    - subtemplates:
      - template: b.yaml # the first request in this template uses the existing JWT and then updates the timestamp
      - template: c.yaml # requests within this template receive the updated JWT

• Restricted:

workflows:
  - template: a.yaml
    cookie-reuse: true # cookies set by the "a" template are READ-ONLY and restricted to subtemplates only
    - subtemplates:
      - template: b.yaml 
      - template: c.yaml