Fix rootless and rootful Docker conflict Portainer install on Linux

Run Portainer in rootles Docker socket mode

echo $XDG_RUNTIME_DIR/docker.sock

Restart Portainer

docker run -d \
  -p 8000:8000 \
  -p 9443:9443 \
  --name=portainer \
  --restart=always \
  -v $XDG_RUNTIME_DIR/docker.sock:/var/run/docker.sock \
  -v portainer_data:/data \
  portainer/portainer-ce:2.21.5