Migrate Az.Relay from SDK to autorest (#21572)

* Remove Relay

* Move Relay to wyunchi/relay-removed (#21564)

* Update Relay

* Update ChangeLog.md

---------

Co-authored-by: Azure PowerShell <[email protected]>

Author: wyunchi-ms

src/Relay/Az.Relay.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <PsModuleName>Relay</PsModuleName>
+  </PropertyGroup>
+
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory).., build.proj))\src\Az.autorest.props" />
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory).., build.proj))\src\Az.Post.props" />
+</Project>