Draft: Add the new MUST detector system
This MR ist based on and supersedes !2040 Initially !2040 included also changes to the framework code of CbmRoot. These changes were properly separated and were added with !2101 (merged) such that !2040 only add the code for the new detector system. Beside these changes the current MR also does a lot of code cleanup to have a clean and streamlined code base for a new detector system.