open5gs-master: migrate to debian-bullseye-build

It's a common practice to have a shared '-build' image and base
the '-master' images on top of it to avoid installing same
dependencies across different images.

Finally we can use more recent meson from debian's repositories,
so no need to depend on python and install it using pip.

Change-Id: I93422916b232f686dc27a2ff452e20e73db50f58
Related: SYS#5602

open5gs-master/Dockerfile

@@ -1,19 +1,14 @@
 ARG	REGISTRY=docker.io
-FROM	${REGISTRY}/debian:buster
+ARG	USER
+FROM	$USER/debian-bullseye-build
 
 MAINTAINER Harald Welte <laforge@gnumonks.org>
 
 RUN apt-get update && \
     apt-get upgrade -y && \
     apt-get install -y --no-install-recommends \
-        python3-pip \
-        python3-setuptools \
-        python3-wheel \
+        meson \
         ninja-build \
-        build-essential \
-        flex \
-        bison \
-        git \
         libsctp-dev \
         libgnutls28-dev \
         libgcrypt-dev \
@@ -27,20 +22,13 @@ RUN apt-get update && \
         libcurl4-gnutls-dev \
         iproute2 \
         ca-certificates \
-        netbase \
-        pkg-config && \
+        netbase && \
     apt-get clean
-RUN python3 -m pip install --upgrade pip
-RUN python3 -m pip install meson
-
 
 RUN apt-get update && \
     apt-get upgrade -y && \
     DEBIAN_FRONTEND=noninteractive \
     apt-get install -y --no-install-recommends \
-        git-buildpackage \
-        debhelper \
-        devscripts \
         vim \
         sudo \
         iputils-ping \