install: update script to set PYTHONPATH env var

This is preferable to setting the WorkingDirectory item in
the systemd unit, as its possible to switch between git repos
and installed wheels without requiring root.

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

scripts/install-moonraker.sh

@@ -131,12 +131,13 @@ install_script()
     ENV_FILE="${DATA_PATH}/systemd/moonraker.env"
     if [ ! -f $ENV_FILE ] || [ $FORCE_DEFAULTS = "y" ]; then
         rm -f $ENV_FILE
-        args="MOONRAKER_ARGS=\"${SRCDIR}/moonraker/moonraker.py"
+        args="MOONRAKER_ARGS=\"-m moonraker"
         [ -n "${CONFIG_PATH}" ] && args="${args} -c ${CONFIG_PATH}"
         [ -n "${LOG_PATH}" ] && args="${args} -l ${LOG_PATH}"
         args="${args} -d ${DATA_PATH}"
         args="${args}\""
-        echo $args > $ENV_FILE
+        args="${args}\nPYTHONPATH=\"${SRCDIR}\""
+        echo -e $args > $ENV_FILE
     fi
     [ -f $SERVICE_FILE ] && [ $FORCE_DEFAULTS = "n" ] && return
     report_status "Installing system start script..."
@@ -156,7 +157,6 @@ Type=simple
 User=$USER
 SupplementaryGroups=moonraker-admin
 RemainAfterExit=yes
-WorkingDirectory=${SRCDIR}
 EnvironmentFile=${ENV_FILE}
 ExecStart=${PYTHONDIR}/bin/python \$MOONRAKER_ARGS
 Restart=always