Set ffmpeg+ffprobe paths in Docker container

Will always ensure containers use correct path.

Yes - the arm images have a different path than the amd64 one. This is
caused by the amd64 image using ffmpeg from jellyfin/ffmpeg while the
others use ffmpeg from their distro's repos.

Dockerfile

@@ -22,4 +22,8 @@ COPY --from=ffmpeg / /
 COPY --from=builder /jellyfin /jellyfin
 EXPOSE 8096
 VOLUME /cache /config /media
-ENTRYPOINT dotnet /jellyfin/jellyfin.dll --datadir /config --cachedir /cache
+ENTRYPOINT dotnet /jellyfin/jellyfin.dll \
+    --datadir /config \
+    --cachedir /cache \
+    --ffmpeg /usr/local/bin/ffmpeg \
+    --ffprobe /usr/local/bin/ffprobe

Dockerfile.arm

@@ -30,4 +30,8 @@ RUN apt-get update \
 COPY --from=builder /jellyfin /jellyfin
 EXPOSE 8096
 VOLUME /cache /config /media
-ENTRYPOINT dotnet /jellyfin/jellyfin.dll --datadir /config --cachedir /cache
+ENTRYPOINT dotnet /jellyfin/jellyfin.dll \
+    --datadir /config \
+    --cachedir /cache \
+    --ffmpeg /usr/bin/ffmpeg \
+    --ffprobe /usr/bin/ffprobe

Dockerfile.arm64

@@ -31,4 +31,8 @@ RUN apt-get update \
 COPY --from=builder /jellyfin /jellyfin
 EXPOSE 8096
 VOLUME /cache /config /media
-ENTRYPOINT dotnet /jellyfin/jellyfin.dll --datadir /config --cachedir /cache
+ENTRYPOINT dotnet /jellyfin/jellyfin.dll \
+    --datadir /config \
+    --cachedir /cache \
+    --ffmpeg /usr/bin/ffmpeg \
+    --ffprobe /usr/bin/ffprobe