Improve build speed in Optimizely CMS 12

In Episerver.CMS.UI 12.11 that was released today, we are promised improved build speed in projects by copying shell module files only when they change or are missing.

Formerly, these files were copied and overwritten on every build with the CopyZipFiles.target being executed. In projects where zip modules files are included in the repository (such as modules/_protected/CMS.zip or Shell.zip), those files are no longer overwritten on each build.

The release notes also mention that Optimizely projects on .NET 5/6 should exclude all modules from the source repository because those files are automatically recreated when missing during the dotnet build.

So, time to exclude that modules/_protected folder from source control!