fix(container-creation): add default/override options (#4119)

* fix(container-creation): add default/override options

* fix(container-creation): allow override with empty string on creation

* fix(container-creation): add tooltip & update placeholder

* fix(container-creation): add warning on duplicate

app/docker/components/imageRegistry/por-image-registry.js

@@ -7,6 +7,7 @@ angular.module('portainer.docker').component('porImageRegistry', {
     autoComplete: '<',
     labelClass: '@',
     inputClass: '@',
+    onImageChange: '&',
   },
   require: {
     form: '^form',

app/docker/components/imageRegistry/porImageRegistry.html

@@ -25,6 +25,7 @@
           ng-model="$ctrl.model.Image"
           name="image_name"
           placeholder="e.g. myImage:myTag"
+          ng-change="$ctrl.onImageChange()"
           required
         />
       </div>