All - Ecto.Adapters.SQL.Connection

Part of #38

https://hexdocs.pm/ecto_sql/Ecto.Adapters.SQL.Connection.html#c:all/1

We need to implement this callback so that it returns the latest version of all rows that match the query parameter.

@RobStallion has already done some research on looking into how we can modify the passed in query, which we can then pass on to the `Ecto.Adapters.Postgres.Connection.all` function

https://github.com/RobStallion/alog_adapter/issues/1
https://stackoverflow.com/questions/54690701/is-there-a-way-to-ensure-where-clause-happens-after-distinct