Resolved more warnings, and marked more warning types as errors (#16990)

* Fix warnings SA1111, SA1028, SA1500, IDE1270  in Umbraco.Web.Website, and updated rules.

* Remove warnings: IDE0270: Null check can be simplified

* More SqlServer project warnings resolved

* CS0105 namespace appeared already

* Suppress warning until implementation:

#pragma warning disable CS0162 // Unreachable code detected
#pragma warning disable CS0618 // Type or member is obsolete

CS0162 remove unreachable code
SA1028 remove trailing whitespace
SA1106 no empty statements
CS1570 malformed XML
CS1572 corrected xml parameter
CS1573 param tag added
IDE0007 var not explicit
IDE0008 explicit not var
IDE0057 simplify substring
IDE0074 compound assignment
CA1825 array.empty

Down to 3479 warnings

tests/Umbraco.Tests.Integration/Testing/TestWebProfilerRepository.cs

@@ -5,7 +5,7 @@ namespace Umbraco.Cms.Tests.Integration.Testing;
 public class TestWebProfilerRepository : IWebProfilerRepository
 {
     private bool _status = false;
-    
+
     public void SetStatus(int userId, bool status) => _status = status;
 
     public bool GetStatus(int userId) => _status;