LXC images with stable apkg

See ci/lxc/README.md

ci/lxc/centos-7/Dockerfile

+FROM registry.nic.cz/labs/lxc-gitlab-runner/centos-7
+
+WORKDIR /root
+CMD ["/bin/bash"]
+
+# overcome locale issues
+RUN yum install -y glibc-common
+RUN localedef -i en_US -f UTF-8 C.UTF-8
+
+# upgrade system to latest
+RUN yum upgrade -y
+# enable EPEL
+RUN yum install -y epel-release
+
+# packaging deps
+RUN yum install -y \
+    git \
+    rpm-build \
+    python3-setuptools \
+    python3-pip
+# basic deps
+RUN pip3 install \
+    beautifulsoup4 \
+    blessings \
+    cached-property \
+    click \
+    distro \
+    jinja2 \
+    packaging \
+    requests \
+    toml
+# install stable apkg from PyPI
+RUN python3 -m pip install apkg
+RUN apkg --version