Adding python3 virtualenv to python systemd services

scripts/install_services.sh

@@ -9,6 +9,8 @@ config_file=$my_dir/birdnet.conf
 export USER=$USER
 export HOME=$HOME
 
+export PYTHON_VIRTUAL_ENV="$HOME/BirdNET-Pi/birdnet/bin/python3"
+
 install_depends() {
   apt install -y debian-keyring debian-archive-keyring apt-transport-https
   curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/gpg.key' | sudo tee /etc/apt/trusted.gpg.d/caddy-stable.asc
@@ -66,7 +68,7 @@ Restart=always
 Type=simple
 RestartSec=10
 User=${USER}
-ExecStart=/usr/local/bin/server.py
+ExecStart=$PYTHON_VIRTUAL_ENV /usr/local/bin/server.py
 [Install]
 WantedBy=multi-user.target
 EOF
@@ -325,7 +327,7 @@ Restart=always
 RestartSec=120
 Type=simple
 User=$USER
-ExecStart=/usr/local/bin/daily_plot.py
+ExecStart=$PYTHON_VIRTUAL_ENV /usr/local/bin/daily_plot.py
 [Install]
 WantedBy=multi-user.target
 EOF