Provide users with useful metadata while workflow is running

[GeigerJ2]

This could be, for one, a metadata file in the run directory, containing the date, and current parameter set, etc., similar to the file that is created on verdi process dump. In addition to what the WG GUI already provides.

[leclairm]

Ideally, scripts ran in shell tasks should have access to the following:

• self:
  • begin date
  • end date
  • parameters
• inputs:
  • path
  • port
  • begin date
  • end date
  • parameters

For python scripts one solution is to dump a yaml file in the task working directory containing this information. It would be easy to document how to parse it. That would be the advised solution if all the above info is required.

For shell scripts, parsing a yaml file would be more difficult but port and path are already available through the command line. We could just add 2 environment variables for the task begin and end dates.

[leclairm]

Closing as duplicate of #61