Foreman » Smart Proxy

Fixes #36890 - Use PrivateTmp in systemd service

Fixes #31118 - Remove daemonize support

Currently Smart Proxy is able to daemonize and manage a pid file.
However, in the common deployments under systemd and Windows this isn't
actually used. There are also other solutions out there to manage it
externally if it's needed....

Fixes #34624 - Set MALLOC_ARENA_MAX to counter memory bloating

fixes #19480 - add systemd notify support

When started under systemd, the launcher now logs via the notify socket
API when all configured WEBrick servers have started so the service
state is reported accurately (rather than the daemonization point).

An example unit file is now shipped that uses a --no-daemonize...