bus-proxy: turn into multi-threaded daemon Instead of using Accept=true and running one proxy for each connection, we now run one proxy-daemon with a thread per connection. This will enable us to share resources like policies in the future.

Use /var/run/dbus/system_bus_socket for the D-Bus socket

units: properly make bus proxy socket of type Accept=yes

bus: install systemd-bus-proxyd unit files for compatibility with dbus1