feat(node): configure system environment through the desktop workflow

apps/node-agent/packaging/prerm

@@ -1,5 +1,14 @@
 #!/bin/sh
 set -eu
+if [ -d /run/systemd/system ]; then
+  mc_node_environment_state=$(systemctl show --property=ActiveState --value mission-core-node-environment.service 2>/dev/null || true)
+  case "$mc_node_environment_state" in
+    active|activating)
+      echo "Mission Core Node: дождитесь завершения настройки окружения в приложении." >&2
+      exit 1
+      ;;
+  esac
+fi
 case "$1" in
   remove|deconfigure)
     mc_node_ssh_snippet=/etc/ssh/sshd_config.d/60-mission-core-node.conf
@@ -11,9 +20,15 @@ case "$1" in
         mv "$mc_node_ssh_snippet" "$mc_node_saved_snippet"
       fi
     fi
+    mc_node_environment_snippet=/etc/systemd/system/mission-core-node.service.d/60-environment.conf
+    if [ ! -L "$mc_node_environment_snippet" ] && cmp -s /usr/share/mission-core-node/60-environment.conf "$mc_node_environment_snippet"; then
+      rm "$mc_node_environment_snippet"
+    fi
     if [ -d /run/systemd/system ]; then
-      /usr/sbin/sshd -t
-      systemctl try-reload-or-restart ssh.service
+      if [ -x /usr/sbin/sshd ]; then
+        /usr/sbin/sshd -t
+        systemctl try-reload-or-restart ssh.service
+      fi
       systemctl stop mission-core-node.service
       systemctl disable mission-core-node.service
     fi