Support arkCpuAffinity and arkPriorityBoost options for systemd

[Caelin]

Current systemd service doesn't support arkCpuAffinity or arkPriorityBoost options from the arkmanager configuration files. This is a feature request to add a command to arkmanager to generate the necessary systemd service files to support these two options.

For systemd the options map as follows:

arkCpuAffinity -> CPUAffinity
arkPriorityBoost -> Nice

Example systemctl service configuration (/etc/systemd/system/[email protected]):

[Unit]
Description=Daemon to start an ark server instance

[Service]
User=steam
ExecStart=/usr/local/bin/arkmanager start --no-background @%i
Type=simple
CPUAffinity=1,2
Nice=-10