[REF] *: BS4, adapt col-related classes

col-lg-* -> col-xl-*
col-md-* -> col-lg-*
col-sm-* -> col-md-*
col-xs-* -> col-*

col-lg-offset-* -> offset-xl-*
col-md-offset-* -> offset-lg-*
col-sm-offset-* -> offset-md-*
col-xs-offset-* -> offset-*

col-lg-pull-* -> order-xl-1
col-md-pull-* -> order-lg-1
col-sm-pull-* -> order-md-1
col-xs-pull-* -> order-1

col-lg-push-* -> order-xl-2
col-md-push-* -> order-lg-2
col-sm-push-* -> order-md-2
col-xs-push-* -> order-2

addons/web/static/src/js/fields/basic_fields.js

@@ -2689,7 +2689,7 @@ var ImageSelection = AbstractField.extend({
         var self = this;
         this.$el.empty();
         _.each(this.nodeOptions, function (val, key) {
-            var $container = $('<div>').addClass('col-xs-3 text-center');
+            var $container = $('<div>').addClass('col-3 text-center');
             var $img = $('<img>')
                 .addClass('img img-fluid img-thumbnail ml16')
                 .toggleClass('btn-info', key === self.value)