Do not use the default logo as icon without telling me

[nbrignol]

Feature Request

Motivation Behind Feature

When I start a new blank app, it's convenient to have the Cordova default logo for my app.
BUT when I start to put my own icons and the platform update add some new size (in the xasset), it use the default logo again.
It quite dangerous because I don't know that, and it's very easy to publish an app with these default icons.

Feature Description

Add a warning on the build phase when using the default logo if there is no custom icon;
Add an error if there is some custom icon, but not all are present.

Alternatives or Workarounds

For now I have to check manually the xasset filme

[dpogue]

With cordova-ios 8 and newer, the default behaviour is to use a single 1024×1024 image that Xcode will scale automatically for all the icon sizes, which should alleviate most of this issues when new icon sizes are introduced.