* Add CPM download script
* Download nholthaus/units@2.3.3
* Download google/googletest@1.12.1
* Add doc target
* Add test target
* Skip unused units

Signed-off-by: Martin Stump <martin.stump@mercedes-benz.com>

The concrete key/value pairs can be discussed in the course of further development.

To install cmake-format on your Linux platform please use: "pip3 install cmakelang[YAML]".
To enable CMake formatting in VSCode please install extension: "cheshirekow.cmake-format".

Signed-off-by: Jupp Tscheak <jupp.tscheak@daimler.com>