Add description, cleanup, reducing size

Dockerfile

@@ -4,31 +4,29 @@ FROM alpine:3.18
 ARG BUILD_DATE
 ARG VERSION
 ARG WEBAPP_VERSION
+
 LABEL build_version="netboot.xyz version: ${VERSION} Build-date: ${BUILD_DATE}"
 LABEL maintainer="antonym"
+LABEL org.opencontainers.image.description netboot.xyz official docker container - Your favorite operating systems in one place. A network-based bootable operating system installer based on iPXE.
 
 RUN \
- apk upgrade --no-cache && \
- apk add --no-cache --virtual=build-dependencies \
-        nodejs npm && \
- echo "**** install runtime packages ****" && \
  apk add --no-cache \
-        bash \
-        busybox \
-        curl \
-        git \
-        jq \
-        nghttp2-dev \
-        nginx \
-        nodejs \
-        shadow \
-        sudo \
-        supervisor \
-        syslog-ng \
-        tar \
-        tftp-hpa
-
-RUN \
+   bash \
+   busybox \
+   curl \
+   git \
+   jq \
+   nghttp2-dev \
+   nginx \
+   nodejs \
+   shadow \
+   sudo \
+   supervisor \
+   syslog-ng \
+   tar \
+   tftp-hpa && \
+ apk add --no-cache --virtual=build-dependencies \
+   npm && \
  groupmod -g 1000 users && \
  useradd -u 911 -U -d /config -s /bin/false nbxyz && \
  usermod -G users nbxyz && \
@@ -39,13 +37,13 @@ RUN \
         WEBAPP_VERSION=$(curl -sX GET "https://api.github.com/repos/netbootxyz/webapp/releases/latest" \
         | awk '/tag_name/{print $4;exit}' FS='[""]'); \
  fi && \
- curl -o \
- /tmp/webapp.tar.gz -L \
+ curl -o /tmp/webapp.tar.gz -L \
         "https://github.com/netbootxyz/webapp/archive/${WEBAPP_VERSION}.tar.gz" && \
- tar xf \
- /tmp/webapp.tar.gz -C \
+ tar xf /tmp/webapp.tar.gz -C \
         /app/ --strip-components=1 && \
- npm install --prefix /app
+ npm install --prefix /app && \
+ apk del --purge build-dependencies && \
+ rm -rf /tmp/*
 
 ENV TFTPD_OPTS=''