Remove UTF-8 BOM from all files (#11821)

As VS 2022 doesn't seem to store files with UTF-8 BOM as often anymore, we've
been getting more and more pull requests which seemingly randomly change files.
This cleans the situation up by removing the BOM from all files that have one.
Additionally, `Host.Tests.Feature.rc` was converted from UTF-16 to UTF-8.

samples/ReadConsoleInputStream/ReadConsoleInputStream.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Concurrent;
 using System.Diagnostics;
 using System.IO;