Add multi-staged dockerfile to build VobSub2SRT

packaging/Dockerfile

@@ -0,0 +1,20 @@
+#
+# To build for arm, see https://www.docker.com/blog/getting-started-with-docker-for-arm-on-linux/
+
+ARG VERSION=v1.0pre7
+ARG TARGET=debian
+
+FROM alpine AS source
+RUN apk add git
+ARG VERSION
+RUN git clone --depth=1 -b $VERSION https://github.com/ruediger/VobSub2SRT /source
+
+FROM debian:buster AS build-debian
+RUN apt update && apt install -y libtiff5-dev libtesseract-dev tesseract-ocr-eng build-essential cmake pkg-config
+
+FROM build-$TARGET AS build
+WORKDIR /build
+COPY --from=source /source .
+RUN ./configure
+RUN make
+RUN make install