Refactor dockerfile to reduce build time

Dockerfile

@@ -0,0 +1,72 @@
+FROM debian:buster AS builder
+
+# Build-time dependencies
+RUN apt-get update -yq && apt-get install -yq \
+		ca-cerqtificates \
+		build-essential \
+		pkg-config \
+		qt5-default \
+		libqt5svg5* \
+		libboost-dev \
+		libasound2-dev \
+		libssl-dev \
+		libspeechd-dev \
+		libzeroc-ice-dev \
+		libpulse-dev \
+		libcap-dev \
+		libprotobuf-dev \
+		libprotoc-dev \
+		protobuf-compiler \
+		protobuf-compiler-grpc \
+		libgrpc++-dev \
+		libogg-dev \
+		libavahi-compat-libdnssd-dev \
+		libsndfile1-dev \
+		libbz2-dev \
+		libxi-dev \
+		git --no-install-recommends
+
+WORKDIR /usr/src/murmur
+RUN \
+    git clone https://github.com/mumble-voip/mumble.git . \
+	&& git checkout master \
+	&& git submodule init \
+	&& git submodule update
+
+RUN \
+    qmake -recursive main.pro CONFIG+="no-client no-g15 no-bonjour grpc" \
+	&& make release \
+	&& cp -r release/ /home/user/release \
+	&& chmod a+r release -R
+
+
+FROM debian:buster
+EXPOSE 64738/tcp 64738/udp
+
+ENV HOME /home/user
+RUN useradd --create-home --home-dir $HOME user \
+	&& chown -R user:user $HOME
+
+WORKDIR $HOME
+
+# Runtime dependencies
+RUN apt-get update && apt-get install -yq \
+		ca-certificates \
+		'libprotobuf[0-9]+$' \
+		libqt5core5a \
+		libqt5dbus5 \
+		libqt5xml5 \
+		libqt5sql5 \
+		libqt5network5 \
+		libcap2 \
+		'libgrpc[0-9]+$' \
+		libgrpc++1 \
+		libzeroc-ice3.7 \
+	&& apt-get clean && rm -rf /var/lib/apt/lists/*
+
+COPY --from=builder /usr/src/murmur/release/murmurd /usr/bin/murmurd
+
+USER user
+
+ENTRYPOINT [ "/usr/bin/murmurd" ]
+CMD [ "-fg", "-v", "-ini", "/data/murmur.ini" ]