Containerfile : install util-linux-core in runtime

The `nsenter` binary is required as it's called before calling
`bootc status`. Let's install the RPM that ships it into the runtime
image.
This is not great as it pulls a lot of dependencies, so later on we
should probably do that in go.

Also make the containerfile use build args so we can use overrides to
pul the hummingbird images from another repo

Signed-off-by: jbtrystram <jbtrystram@redhat.com>

Author: jbtrystram

Containerfile

@@ -1,4 +1,24 @@
-FROM quay.io/hummingbird/go AS builder
+ARG GO_BUILDER_IMAGE=quay.io/hummingbird/go:latest-builder
+ARG CORE_RUNTIME_IMAGE=quay.io/hummingbird/core-runtime:latest
+
+
+FROM ${GO_BUILDER_IMAGE} AS deps
+# We pull required dependencies and overlay them
+# on top of the runtime image
+ARG DNF_FLAGS="-y --setopt=install_weak_deps=False --nodocs"
+RUN --mount=type=cache,id=dnf,target=/var/cache/libdnf5 \
+    mkdir -p /staged &&\
+    dnf install -y \
+        --use-host-config \
+        --installroot=/staged \
+        util-linux-core && \
+    # Remove metadata and manpages
+    rm -rf /staged/var/lib/dnf \
+        /staged/var/log/* \
+        /staged/var/lib/rpm \
+        /staged/usr/share/{man,doc,locale}
+
+FROM ${GO_BUILDER_IMAGE} AS builder
 
 ARG VERSION=dev
 ARG GIT_COMMIT=unknown
@@ -13,7 +33,8 @@ RUN --mount=type=cache,id=gomod,target=/root/go/pkg/mod \
     go build -ldflags "${LDFLAGS}" -o manager ./cmd/controller/ && \
     go build -ldflags "${LDFLAGS}" -o daemon ./cmd/daemon/
 
-FROM quay.io/hummingbird/core-runtime:latest
+FROM ${CORE_RUNTIME_IMAGE}
+COPY --from=deps /staged/usr /usr
 COPY --from=builder /workspace/manager /workspace/daemon /usr/local/bin/
 USER 65532:65532
 ENTRYPOINT ["manager"]