scripts/modelsim.ini

the following line at the end

# do not delete this line
# -----------------------------------------------------------------------------

to start vsim as background process, added & for target sim

- added file scripts/design_project_directory_structure.txt
- added credentials for Friedrich Beckmann in header blocks
- added appropriate comments to understand makefiles
- moved testbenches and test environment source files to src dir

added -modelsimini ../../scripts/modelsim.ini