How do I create a pure solution-level NuGet package

问题

I want to create and distribute a NuGet package that when installed only installs solution-wide to the root packages-folder, referencing the package in the .NuGet\packages.config file.

I have found some information on the NuGet package format in regards to this topic already and according to NuGet FAQ this should be possible if one follow these guidelines:

What is the difference between a project-level package and a solution-level package?

A solution-level package has to be installed only once in a solution to be available for all projects in the solution. A project-level package must be installed separately in each project where you want to use it. For solution-level packages, NuGet doesn't change anything in a project, whereas in a project-level package it does. Typically, a solution-level package installs new commands that can be called from within the Package Manager Console window.

Another Suggested SO solution states that the above should have worked too.

Thing is, I can't get it this to work. I have verified that my package has no lib or content directories:

I have put all the files to distribute in the tools-folder in the package, including the init.ps1` script top run on install.

I am using Visual Studio 2015 and when I want to install the package:

I first of all have to select a project to install to. I had expected not having to specify this, as it is supposed to be solution-wide. :/
The init.ps1 script does run and executes the commands as I want them to do. :)
But, a packages-folder is created in the project that I was forced to choose to get the installation done. I would have expected the packages-folder to be created in the solution-root. :(
Also, the packages.config file is created in the project-folder and not in .NuGet\packages.config, as I'd expect after reading the docs I have found on this. :(