Add Pi signage Phase 1 player artifacts

Squash merge Sprint 14 Pi signage player artifacts.

apps/fc-signage-pi-player/systemd/flowercore-signage-player-pi.service

@@ -0,0 +1,30 @@
+[Unit]
+Description=FlowerCore Digital Signage Pi Player (Chromium kiosk)
+Documentation=https://github.com/astoltz/FlowerCore.Notes/blob/master/docs/standards/appletv-pi-signage-agents-design.md
+Wants=network-online.target
+After=network-online.target graphical.target
+ConditionPathExists=/etc/flowercore/signage-node.json
+ConditionPathExists=/etc/fc-signage-player/client.p12
+
+[Service]
+Type=simple
+User=fc-signage
+Group=fc-signage
+WorkingDirectory=/var/lib/fc-signage-player
+EnvironmentFile=-/etc/flowercore/signage-player.env
+ExecStartPre=/usr/local/bin/flowercore-signage-prelaunch.sh
+ExecStart=/usr/local/bin/flowercore-signage-launch.sh
+Restart=always
+RestartSec=10s
+StartLimitBurst=5
+StartLimitIntervalSec=300s
+MemoryMax=2G
+MemoryHigh=1500M
+ProtectSystem=strict
+ProtectHome=true
+ReadWritePaths=/var/lib/fc-signage-player /var/log/fc-signage-player
+PrivateTmp=true
+NoNewPrivileges=true
+
+[Install]
+WantedBy=graphical.target