Add warning when editor is changing a recipe warehouse path

[benoit74]

When the user is changing the warehouse path of a recipe which already produced a ZIM, Zimfarm will display a warning like "Changing the warehouse path of a recipe is not a minor change. You need to first move all existing ZIMs to the new target warehouse path."

This could help to avoid issues like kiwix/operations#181

Not sure it is easy to detect if the recipe already produced a ZIM, if it is too cumbersome we can display the warning whenever the recipe already succeeded once. It is is too cumbersome, we can display the warning whenever the user is changing the warehouse path.

@Popolechien @RavanJAltaie @kelson42 @rgaudin does it make sense to you? Any better wording to propose?

[rgaudin]

Let's try this. If it's too annoying, we'll revert.

[RavanJAltaie]

Let's try this. If it's too annoying, we'll revert.

I agree.