feat: execute service as distributed erlang (#96)

To create a cluster with distributed nodes, the following changes were made:

* Use [`dns_cluster`][0] to execute distributed nodes
* Add _script_ to execute distributed nodes locally

Also, improve local execution by:

* Use [`mix release`][1] to make easier [deploy `phoenix`][2]
* Use [`compose watch`][3] to synchronize code from the host with the service

Some minor improvements:

* Ignore files and folders in git and docker
* Remove boilerplate comments

[0]: https://github.com/phoenixframework/dns_cluster
[1]: https://hexdocs.pm/mix/Mix.Tasks.Release.html
[2]: https://hexdocs.pm/phoenix/releases.html
[3]: https://docs.docker.com/compose/how-tos/file-watch/

Co-authored-by: Joao P Dubas <joao.dubas@gmail.com>
Reviewed-on: #96
Co-authored-by: Joao P Dubas <joao.dubas+gitea@gmail.com>
Co-committed-by: Joao P Dubas <joao.dubas+gitea@gmail.com>

config/prod.exs

@@ -1,55 +1,7 @@
 import Config
 
-# For production, don't forget to configure the url host
-# to something meaningful, Phoenix uses this information
-# when generating URLs.
-#
-# Note we also include the path to a cache manifest
-# containing the digested version of static files. This
-# manifest is generated by the `mix phx.digest` task,
-# which you should run after static files are built and
-# before starting your production server.
 config :wabanex, WabanexWeb.Endpoint,
   url: [host: "example.com", port: 80],
   cache_static_manifest: "priv/static/cache_manifest.json"
 
-# Do not print debug messages in production
 config :logger, level: :info
-
-# ## SSL Support
-#
-# To get SSL working, you will need to add the `https` key
-# to the previous section and set your `:url` port to 443:
-#
-#     config :wabanex, WabanexWeb.Endpoint,
-#       ...
-#       url: [host: "example.com", port: 443],
-#       https: [
-#         port: 443,
-#         cipher_suite: :strong,
-#         keyfile: System.get_env("SOME_APP_SSL_KEY_PATH"),
-#         certfile: System.get_env("SOME_APP_SSL_CERT_PATH"),
-#         transport_options: [socket_opts: [:inet6]]
-#       ]
-#
-# The `cipher_suite` is set to `:strong` to support only the
-# latest and more secure SSL ciphers. This means old browsers
-# and clients may not be supported. You can set it to
-# `:compatible` for wider support.
-#
-# `:keyfile` and `:certfile` expect an absolute path to the key
-# and cert in disk or a relative path inside priv, for example
-# "priv/ssl/server.key". For all supported SSL configuration
-# options, see https://hexdocs.pm/plug/Plug.SSL.html#configure/1
-#
-# We also recommend setting `force_ssl` in your endpoint, ensuring
-# no data is ever sent via http, always redirecting to https:
-#
-#     config :wabanex, WabanexWeb.Endpoint,
-#       force_ssl: [hsts: true]
-#
-# Check `Plug.SSL` for all available options in `force_ssl`.
-
-# Finally import the config/prod.secret.exs which loads secrets
-# and configuration from environment variables.
-import_config "prod.secret.exs"