Add systemd unit, requirements.txt and venv setup docs

raspi-cam.service

@@ -0,0 +1,16 @@
+[Unit]
+Description=Raspberry Pi Camera MJPEG Stream Server
+After=network.target
+
+[Service]
+Type=simple
+User=joachim
+Group=video
+WorkingDirectory=/home/joachim/git/raspi-cam
+ExecStart=/home/joachim/git/raspi-cam/venv/bin/python /home/joachim/git/raspi-cam/app.py
+Restart=always
+RestartSec=3
+Environment=PYTHONUNBUFFERED=1
+
+[Install]
+WantedBy=multi-user.target