Creation of a new Teiid instance in the JBDS Teiid Designer should prompt the user to make that the default

When you create a new Teiid instance, and one already existed, the user should be prompted if they want this new instance to be the default since many of the other actions automatically use the default server without giving the user a chance to explicitly select one. The alternative, of course, would be to change all of the other actions to allow an explicit selection.