Merge remote-tracking branch 'origin/v8/dev' into netcore/dev

# Conflicts:
#	src/Umbraco.Abstractions/Constants-AppSettings.cs
#	src/Umbraco.Abstractions/ContentVariationExtensions.cs
#	src/Umbraco.Abstractions/IMainDom.cs
#	src/Umbraco.Abstractions/PropertyEditors/MultiUrlPickerConfiguration.cs
#	src/Umbraco.Abstractions/Runtime/IMainDom.cs
#	src/Umbraco.Abstractions/Runtime/MainDom.cs
#	src/Umbraco.Core/IMainDom.cs
#	src/Umbraco.Core/MainDom.cs
#	src/Umbraco.Core/Umbraco.Core.csproj
#	src/Umbraco.Infrastructure/MainDom.cs
#	src/Umbraco.Infrastructure/Migrations/Upgrade/UmbracoPlan.cs
#	src/Umbraco.Infrastructure/Runtime/CoreRuntime.cs
#	src/Umbraco.Web.UI/Umbraco/config/lang/en.xml
#	src/Umbraco.Web/Models/Mapping/ContentTypeMapDefinition.cs
#	src/Umbraco.Web/PublishedCache/NuCache/ContentStore.cs
#	src/Umbraco.Web/UmbracoApplication.cs
#	src/Umbraco.Web/UmbracoComponentRenderer.cs

src/Umbraco.Infrastructure/Persistence/Repositories/Implement/ContentTypeRepositoryBase.cs

@@ -1326,6 +1326,17 @@ WHERE {Constants.DatabaseSchema.Tables.Content}.nodeId IN (@ids) AND cmsContentT
             return Database.ExecuteScalar<int>(sql) > 0;
         }
 
+        /// <summary>
+        /// Returns true or false depending on whether content nodes have been created based on the provided content type id.
+        /// </summary>
+        public bool HasContentNodes(int id)
+        {
+            var sql = new Sql(
+                $"SELECT CASE WHEN EXISTS (SELECT * FROM {Constants.DatabaseSchema.Tables.Content} WHERE contentTypeId = @id) THEN 1 ELSE 0 END",
+                new { id });
+            return Database.ExecuteScalar<int>(sql) == 1;
+        }
+
         protected override IEnumerable<string> GetDeleteClauses()
         {
             // in theory, services should have ensured that content items of the given content type