docker: variable DUNITER_PUBLIC_ADDR

When this variable exists and is not empty, add this option:
  --public-addr "$DUNITER_PUBLIC_ADDR"

Example:
  DUNITER_PUBLIC_ADDR=/dns/example.com/tcp/443/wss

docker/docker-entrypoint

@@ -29,6 +29,10 @@ fi
 _DUNITER_PEER_ID="$(duniter key inspect-node-key --file "$_DUNITER_KEY_FILE")"
 echo "Node peer ID is '$_DUNITER_PEER_ID'."
 
+if [ -n "$DUNITER_PUBLIC_ADDR" ]; then
+  set -- "$@" --public-addr "$DUNITER_PUBLIC_ADDR"
+fi
+
 DUNITER_DISABLE_PROMETHEUS=$(boolean "${DUNITER_DISABLE_PROMETHEUS:-false}")
 
 DUNITER_CHAIN_NAME="${DUNITER_CHAIN_NAME:-dev}"