Netcore: Align namespaces (#9801)

* Rename Umbraco.Core namespace to Umbraco.Cms.Core

* Move extension methods in core project to Umbraco.Extensions

* Move extension methods in core project to Umbraco.Extensions

* Rename Umbraco.Examine namespace to Umbraco.Cms.Examine

* Move examine extensions to Umbraco.Extensions namespace

* Reflect changed namespaces in Builder and fix unit tests

* Adjust namespace in Umbraco.ModelsBuilder.Embedded

* Adjust namespace in Umbraco.Persistence.SqlCe

* Adjust namespace in Umbraco.PublishedCache.NuCache

* Align namespaces in Umbraco.Web.BackOffice

* Align namespaces in Umbraco.Web.Common

* Ensure that SqlCeSupport is still enabled after changing the namespace

* Align namespaces in Umbraco.Web.Website

* Align namespaces in Umbraco.Web.UI.NetCore

* Align namespaces in Umbraco.Tests.Common

* Align namespaces in Umbraco.Tests.UnitTests

* Align namespaces in Umbraco.Tests.Integration

* Fix errors caused by changed namespaces

* Fix integration tests

* Undo the Umbraco.Examine.Lucene namespace change

This breaks integration tests on linux, since the namespace wont exists there because it's only used on windows.

* Fix merge

* Fix Merge

src/Umbraco.Core/IO/IOHelperLinux.cs

@@ -1,9 +1,9 @@
 using System;
 using System.IO;
 using System.Linq;
-using Umbraco.Core.Hosting;
+using Umbraco.Cms.Core.Hosting;
 
-namespace Umbraco.Core.IO
+namespace Umbraco.Cms.Core.IO
 {
     public class IOHelperLinux : IOHelper
     {