This should finalize the build.

daemon.json

-{ "insecure-registries": ["mc.felinewith.me:5000"] }
\ No newline at end of file

mvn-entrypoint.sh

+#! /bin/bash -eu
+
+set -o pipefail
+
+# Copy files from /usr/share/maven/ref into ${MAVEN_CONFIG}
+# So the initial ~/.m2 is set with expected content.
+# Don't override, as this is just a reference setup
+copy_reference_file() {
+  local root="${1}"
+  local f="${2%/}"
+  local logfile="${3}"
+  local rel="${f/${root}/}" # path relative to /usr/share/maven/ref/
+  echo "$f" >> "$logfile"
+  echo " $f -> $rel" >> "$logfile"
+  if [[ ! -e ${MAVEN_CONFIG}/${rel} || $f = *.override ]]
+  then
+    echo "copy $rel to ${MAVEN_CONFIG}" >> "$logfile"
+    mkdir -p "${MAVEN_CONFIG}/$(dirname "${rel}")"
+    cp -r "${f}" "${MAVEN_CONFIG}/${rel}";
+  fi;
+}
+
+copy_reference_files() {
+  local log="$MAVEN_CONFIG/copy_reference_file.log"
+
+  if (touch "${log}" > /dev/null 2>&1)
+  then
+      echo "--- Copying files at $(date)" >> "$log"
+      find /usr/share/maven/ref/ -type f -exec bash -eu -c 'copy_reference_file /usr/share/maven/ref/ "$1" "$2"' _ {} "$log" \;
+  else
+    echo "Can not write to ${log}. Wrong volume permissions? Carrying on ..."
+  fi
+}
+
+export -f copy_reference_file
+copy_reference_files
+
+exec "$@"

settings-docker.xml

+<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0
+                      https://maven.apache.org/xsd/settings-1.0.0.xsd">
+  <localRepository>/usr/share/maven/ref/repository</localRepository>
+</settings>