Warn users of impact when deleting a view via Fauxton

## Summary

Fauxton allows one to easily delete a view. If they do, then *all* views will be rebuilt. That might be sensible behavior if one were to think about how design documents work, but it's not obvious behavior. If you have several large views and delete one to reduce your storage requirements, all the rest will become unavailable until they're rebuilt. For large databases, this might take days. In that sense, being able to easily delete views is a giant footgun.

My team and I found this the hard way out a couple of months ago and it cost us.

## Desired Behaviour

To us it would make sense for some friction to be introduced in the UX when a change with potential catastrophic impact is made. Ideally, we would have liked to have been warned about views being rebuilt and the potential for downtime.

The above assumes that making it so that one could delete one view without rebuilding the others is too effortful to consider. It would otherwise be the ideal behavior.

## Possible Solution

Something as simple as an alert, explaining that other views would have to be rebuilt, causing downtime, would suffice.

Start in Fauxton's view-deletion flow and trace what happens when a view is removed. The change is done when the UI warns that deleting a view rebuilds the other views and may cause downtime before the user confirms.

Written by the indexing model from the issue text.