Add missing required code generation package

Without this tool, the command in part 2 for code generation will fail with the message below
```
To scaffold controllers and views using models, install Entity Framework core packages and try again: Microsoft.EntityFrameworkCore.Tools
   at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.<BuildCommandLine>b__6_0()
   at Microsoft.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args)
   at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.Execute(String[] args)
   at Microsoft.VisualStudio.Web.CodeGeneration.CodeGenCommand.Execute(String[] args)
```

aspnetcore/includes/add-EF-NuGet-SQLite-CLI-7.md

@@ -9,6 +9,7 @@ dotnet add package Microsoft.EntityFrameworkCore.Design
 dotnet add package Microsoft.EntityFrameworkCore.SQLite
 dotnet add package Microsoft.VisualStudio.Web.CodeGeneration.Design
 dotnet add package Microsoft.EntityFrameworkCore.SqlServer
+dotnet add package Microsoft.EntityFrameworkCore.Tools
 ```
 
 The preceding commands add: