Use local Date reference to "now"

Right now every time we want to use a date, at least a current date, we are using: `DateTime.utc_now()`.

While it's ok, it's still subject to fluctuations, so in order to leverage later a date synchronization with #223, we can use a local reference which will act as current time.

For now, it can be seen as a simple function returning: `DateTime.utc_now()` but with this abstraction we could evolve later with other logic we would like to implement.

Search the Elixir codebase for uses of DateTime.utc_now() and identify the appropriate local date reference entry point. Read issue #223 for the planned synchronization context; done means current-date access uses the abstraction while initially retaining DateTime.utc_now() behavior.

Written by the indexing model from the issue text.