[build-tools] remove old .NET 6 installers (dotnet#6861)

Prior to the `dotnet workload` command existing, we had to produce
installers ourselves for early .NET 6 previews. We had one-off
packages produced by `create-dotnet-msi.csproj` and
`create-dotnet-pkg.csproj`.

We can also delete the `<ConvertToRichText/>` and `<GenerateWixFile/>`
tasks, which were only used to create the `.msi`.

Configuration.props

@@ -81,7 +81,6 @@
     <AndroidSdkDirectory Condition=" '$(AndroidSdkDirectory)' == '' ">$(AndroidToolchainDirectory)\sdk</AndroidSdkDirectory>
     <AndroidNdkDirectory Condition=" '$(AndroidNdkDirectory)' == '' And Exists($(ANDROID_NDK_LATEST_HOME)) ">$(ANDROID_NDK_LATEST_HOME)</AndroidNdkDirectory>
     <AndroidNdkDirectory Condition=" '$(AndroidNdkDirectory)' == '' ">$(AndroidToolchainDirectory)\ndk</AndroidNdkDirectory>
-    <WixToolPath Condition=" '$(WixToolPath)' == '' ">$(AndroidToolchainDirectory)\wix\</WixToolPath>
     <AndroidCmakeVersion Condition=" '$(AndroidCmakeVersion)' == '' ">3.18.1</AndroidCmakeVersion>
     <AndroidCmakeUrlPrefix Condition=" '$(HostOS)' == 'Windows' And '$(AndroidCmakeUrlPrefix)' == '' ">7c386a739f915f5bd60051f2572c24782388e807.</AndroidCmakeUrlPrefix>
     <AndroidCmakeUrlPrefix Condition=" '$(HostOS)' == 'Darwin' And '$(AndroidCmakeUrlPrefix)' == '' ">ba34c321f92f6e6fd696c8354c262c122f56abf8.</AndroidCmakeUrlPrefix>

Documentation/building/windows/instructions.md

@@ -131,13 +131,6 @@ Using the `dotnet-local` script will execute the `dotnet` provisioned in
 
 See the [One .NET Documentation](../../guides/OneDotNet.md) for further details.
 
-# Creating .NET 6 installer
-
-Once `msbuild Xamarin.Android.sln /t:Build` is complete, you can
-create an `.msi` for the .NET 6 Android workload via:
-
-    > msbuild Xamarin.Android.sln /t:CreateWorkloadInstallers
-
 # Building Unit Tests
 
 Once `msbuild Xamarin.Android.sln` has completed, the unit tests may