add scripting utils

[juliettelavoie]

Pull Request Checklist:

• This PR addresses an already opened issue (for bug fixes / features)
  • This PR fixes #xyz
• (If applicable) Documentation has been added / updated (for bug fixes / features).
• (If applicable) Tests have been added.
• This PR does not seem to break the templates.
• HISTORY.rst has been updated (with summary of main changes).
  • Link to issue (:issue:number) and pull request (:pull:number) has been added.

What kind of change does this PR introduce?

• save_and_update: nothing new, just putting things that exists all together so that I only have one line at the end of each tasks.
  ** I removed the "move" part of that function, because we want to encourage Ouranos users to write everything in one place and than use move_and_delete.
• move_and_delete: In a workflow, when a simulation is done, you can save what you want to keep (final, maybe regridded and log file) and delete the workdir.
• added catutils to the API for the docs

Does this PR introduce a breaking change?

no

Other information:

• how do we do tests for io stuff ?
• I am thinking of using these function in template 1, but I am not sure. It might be better to see that save and update are different functions when you are learning xscen? Is move_and_delete too advanced for basic workflow ?

[aulemahal]

Looks good.

I'm also not sure who this can be integrated in the test suite. You could generate a file and move it around, checking that the catalog is updated. It would be a very shallow test...