clean up how extracting tar is done; just put it in /usr/bin instead of symlinks; remove xz-utils after (cleaning up space); all at request of nvllsvm

Dockerfile

@@ -1,4 +1,5 @@
 ARG DOTNET_VERSION=2
+ARG FFMPEG_URL=https://www.johnvansickle.com/ffmpeg/old-releases/ffmpeg-4.0.3-64bit-static.tar.xz
 
 FROM microsoft/dotnet:${DOTNET_VERSION}-sdk as builder
 WORKDIR /repo
@@ -13,15 +14,10 @@ EXPOSE 8096
 
 VOLUME /config /media
 
-RUN apt update
-RUN apt install -y wget xz-utils
-RUN mkdir /ffmpeg
-WORKDIR /ffmpeg
-RUN wget https://www.johnvansickle.com/ffmpeg/old-releases/ffmpeg-4.0.3-64bit-static.tar.xz
-RUN tar xf /ffmpeg/ffmpeg-4.0.3-64bit-static.tar.xz
-RUN ln -s /ffmpeg/ffmpeg-4.0.3-64bit-static/ffmpeg /usr/local/sbin/ffmpeg
-RUN ln -s /ffmpeg/ffmpeg-4.0.3-64bit-static/ffprobe /usr/local/sbin/ffprobe
-
+RUN apt update \
+ && apt install -y xz-utils \
+ && curl ${FFMPEG_URL} | tar Jxf - -C /usr/bin --wildcards --strip-components=1 ffmpeg*/ffmpeg ffmpeg*/ffprobe \
+ && apt remove -y xz-utils
 
 ENTRYPOINT if [ -n "$PUID$PGUID" ]; \
     then echo "PUID/PGID are deprecated. Use Docker user param." >&2; exit 1; \