container: parameterize the sambacc containerfile

Strip down the containerfile to the bare minimum, the base image, the
build.sh script, and dependencies. Make the base image a build arg.
Make the installation of the dependencies optional based on a build arg.

This now makes it possible to more easily test and reuse the sambacc
test (and build) container image for different base OSes. For example:

```
podman build -t sambacc:mini36 --build-arg=SAMBACC_BASE_IMAGE=registry.fedoraproject.org/fedora:36 --build-arg=SAMBACC_MINIMAL=yes -f tests/container/Containerfile
podman run --rm -it sambacc:mini36

podman build -t sambacc:c9s -f tests/container/Containerfile

podman build -t sambacc:mini9 --build-arg=SAMBACC_MINIMAL=yes -f tests/container/Containerfile

podman build -t sambacc:fc37 --build-arg=SAMBACC_BASE_IMAGE=registry.fedoraproject.org/fedora:37 -f tests/container/Containerfile
```

Signed-off-by: John Mulligan <[email protected]>

Author: phlogistonjohn

tests/container/Containerfile

@@ -1,30 +1,14 @@
-FROM registry.fedoraproject.org/fedora:36
+ARG SAMBACC_BASE_IMAGE='registry.fedoraproject.org/fedora:36'
+FROM $SAMBACC_BASE_IMAGE
+
 
-RUN yum install \
-    -y --setopt=install_weak_deps=False \
-    git \
-    mercurial \
-    python-pip \
-    python-pip-wheel \
-    python-setuptools \
-    python-setuptools-wheel \
-    python-tox \
-    python3-samba \
-    python3-wheel \
-    python3-pyxattr \
-    python3-devel \
-    python3.9 \
-    samba-common-tools \
-    rpm-build \
-    'python3dist(flake8)' \
-    'python3dist(inotify-simple)' \
-    'python3dist(mypy)' \
-    'python3dist(pytest)' \
-    'python3dist(pytest-cov)' \
-    'python3dist(setuptools-scm)' \
-    'python3dist(tox-current-env)' \
-    'python3dist(wheel)' \
-    && yum clean all \
-    && true
 COPY build.sh /usr/local/bin/build.sh
+
+# Set SAMBACC_MINIMAL to yes to build a container that only contains the
+# build.sh script on top of the base image. When called, build.sh will
+# automatically install the dependency packages. Installing packages on every
+# run can be slow, especially if you are hacking on the code or tests, so we
+# install those dependencies proactively by default.
+ARG SAMBACC_MINIMAL=no
+RUN if [ "$SAMBACC_MINIMAL" != "yes" ]; then /usr/local/bin/build.sh --install ; fi
 ENTRYPOINT ["/usr/local/bin/build.sh"]