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/test.exs

@@ -1,21 +1,13 @@
 import Config
 
-# Configure your database
-#
-# The MIX_TEST_PARTITION environment variable can be used
-# to provide built-in test partitioning in CI environment.
-# Run `mix help test` for more information.
 config :wabanex, Wabanex.Repo,
   database: "wabanex_test#{System.get_env("MIX_TEST_PARTITION")}",
   pool: Ecto.Adapters.SQL.Sandbox
 
-# We don't run a server during test. If one is required,
-# you can enable the server option below.
 config :wabanex, WabanexWeb.Endpoint,
   http: [port: 4002],
   server: false
 
-# Print only warnings and errors during test
 config :logger, level: :warning
 
 config :junit_formatter,