test: rename test directory
synchronize logger socket with what we use in the code
Use @ instead = as abstract namespace socket prefix @ makes more sense since the NUL addr contained in the sockaddr's sun_path field can also be written as ^@. Also, in the .socket files writing "ListenStream==foo" is kinda ugly. Finally, tools like strace decode it with an @ too.
the systemd logger only matters in the abstract namespace
implement proper logging for services
implement trivial socket activated logger daemon