Configuring ssl in rabbitmq.config using rabbitmq docker image

My goal is to set rabbitmq with ssl support, which was achieved previously using below rabbitmq.config file, which resides in host's /etc/rabbitmq path.

Now I want to be able to configure other rabbitmq user and password than defaults guest guest.

I'm using rabbitmq docker image with following docker-compose configuration:

version: '2'
services:
    rabbitmq:
        build: ./rabbitmq
        ports:
          - "8181:8181"
        expose:
          - "15672"
          - "8181"
        volumes:
          - /etc/rabbitmq:/etc/rabbitmq

        environment:
          RABBITMQ_DEFAULT_USER: user123
          RABBITMQ_DEFAULT_PASS: 1234

Rabbitmq config:

[{rabbit,
  [
    {loopback_users, []},
    {heartbeat,0},
    {ssl_listeners, [8181]},
    {ssl_options, [{cacertfile, "/etc/rabbitmq/ca/cacert.pem"},
                   {certfile,   "/etc/rabbitmq/server/cert.pem"},
                   {keyfile,    "/etc/rabbitmq/server/key.pem"},
                   {verify,verify_none},
                   {fail_if_no_peer_cert,false}]}
  ]}
].

Rabbitmq dockerfile:

from rabbitmq:management

#and some certificate generating logic

I noticed that once upon adding environment section, current rabbitmq.config file is overriden with auto generated configuration possibly by docker-entrypoint.sh file.

For building configuration using the certs I found environment variables that can do this (look here). However didn't found any reference for defining ssl_listeners section with its port, as seen in below rabbitmq.config

My question is: how can I create the exact configuration as mentioned below using env variables OR how can I remain with mine rabbitmq.config defining rabbitmq with new user and password in some dynamic way (maybe templating the config file)?