Refactor CMake configuration, add CTest configuration and a first test

[tmadlener]

BEGINRELEASENOTES

• Cleanup the CMake configuration
  • Make the top level CMakeLists.txt deal with dependency finding and build setup
  • Add dedicated CMakeLists.txt in subfolders and make them define their targets in isolation
• Install the python source files to <prefix>/python
• Add CTest configuration and add the existing check.sh as a first unittest that can be run via ctest
• Remove unnecessary duplicated code

ENDRELEASENOTES