Add documentation about VisualStudio setup

Stuff like the minimal required components should be documented!

❗ It might be necessary to enable the .NET Portable Library targeting pack option as well, has to be tested ❗

Components as shown by the installer:

Components in alphabetial order:

.NET Framework 4.5 targeting pack
.NET Framework 4.5.1 targeting pack
.NET Framework 4.5.2 targeting pack
.NET Framework 4.6 targeting pack
.NET Framework 4.6.1 SDK
.NET Framework 4.6.1 targeting pack
.NET Framework 4.6.2 SDK
.NET Framework 4.6.2 targeting pack
.NET profiling tools
C# and Visual Basic
C# and Visual Basic Roslyn compilers
Class Designer
Dependency Validation
Developer Analytics tools
Git for Windows
Just-In-Time debugger
MSBuild
NuGet package manager
Static analysis tools
Text Template Transformation

See also the build-package-deploy instructions.