Add ecto_sql package

# Feature request

## Summary

We have Ecto library, but it doesnt include the migration commands which is in a separate package - ecto_sql https://hexdocs.pm/ecto_sql/Ecto.Migration.html

## Examples

Review how the existing Ecto library is integrated, then compare it with the ecto_sql documentation at https://hexdocs.pm/ecto_sql/Ecto.Migration.html. Done means ecto_sql documentation is available alongside Ecto, including its migration commands.

Rédigé par le modèle d'indexation à partir du texte de l'issue.