Recipe actions should not be editable after a recipe is created

[Osmose]

#599, #584 and #586 all involve adding server-side behavior that is custom to a specific type of action, and there's potentially confusing edge cases for recipes that change their action. I can't think of a compelling reason to allow users to edit the recipe action after a recipe has been created anyway; they should just create a brand new recipe instead.

@MattGrimes @gregglind @mythmon Thoughts? Objections?

[mythmon]

This isn't something we need for preference experiments.

[andymikulski]

This is a pretty simple one-liner to implement*. The only question I have is could the user change the action when cloning? Pending this feature's approval, this should be a quick fix.

*<ActionSelect disabled={isLoading || recipe.getIn(['action', 'id'])} />

[Osmose]

1. I think cloning should be able to change the action.
2. In a separate PR from the proposed change, I think we want to disallow this on the server side as well as on the client. The eventual goal is to modify our data model to make per-action customization easy.

[MattGrimes]

+1 to osmose

[mythmon]

I think this is both a front-end and back-end issue. The UI should be nice and not expose changing the action after the recipe is created, but also the backend shouldn't allow it, even if the UI does.