Roslyn code analyzer samples contain install.ps1/uninstall.ps1 that are no longer supported

Roslyn code analyzer [samples](https://github.com/dotnet/samples/tree/main/csharp/roslyn-sdk/Tutorials/MakeConst/MakeConst.Package/tools) contain install.ps1/unistall.ps1, but they are no longer supported:
https://devblogs.microsoft.com/nuget/nuget-now-fully-integrated-into-msbuild/#will-existing-nuget-packages-work-if-i-am-using-packagereference-for-wpf-windows-forms-or-asp-net-projects

Additionally, it seems that it's easier to include files in the package using `Content` element instead of using `TargetsForTfmSpecificContentInPackage` in the [project file](https://github.com/dotnet/samples/blob/main/csharp/roslyn-sdk/Tutorials/MakeConst/MakeConst.Package/MakeConst.Package.csproj), like this:

```xml

analyzers\dotnet\cs

```