drop centos8, add almalinux 8.8, update rocky to 8.8

And cleanup Docker files

docker/almalinux-8.8.Dockerfile

@@ -0,0 +1,36 @@
+FROM almalinux:8.8
+
+# install pytest, sshd for test, and rpm-build
+RUN set -ex && yum -y install \
+	python3 python3-pip python3-devel openssh openssh-server openssh-clients rpm-build
+
+RUN python3 -m pip install pytest
+
+
+# preparation for sshd
+RUN  mkdir /var/run/sshd        \
+	&& ssh-keygen -A	\
+        && ssh-keygen -f /root/.ssh/id_rsa -N ""                \
+        && mv /root/.ssh/id_rsa.pub /root/.ssh/authorized_keys
+
+
+ARG mscpdir="/mscp"
+
+COPY . ${mscpdir}
+
+# install build dependency
+RUN ${mscpdir}/scripts/install-build-deps.sh
+
+# build
+RUN cd ${mscpdir}			\
+        && rm -rf build			\
+        && cmake -B build		\
+        && cd ${mscpdir}/build          \
+	&& make				\
+	&& cpack -G RPM CPackConfig.cmake \
+	&& rpm -iv *.rpm
+
+# install mscp python module
+RUN cd ${mscpdir}	\
+	&& python3 setup.py install --user
+