feat: add initial Nexus3 files

nexus3/uid_entrypoint

@@ -0,0 +1,6 @@
+#!/bin/sh
+USER_ID=$(id -u)
+if [ ${USER_UID} != ${USER_ID} ]; then
+    sed "s@${USER_NAME}:x:\${USER_ID}:@${USER_NAME}:x:${USER_ID}:@g" /etc/passwd.template > /etc/passwd
+fi
+exec "$@"