Configuration overhaul: print the final configuration to console

[josecelano]

Parent issue: #591

When the application starts, it only prints the loaded configuration when it's loaded from an env var. It's very helpful to print the final configuration after merging all sources with Figment.

deafults values -> merge with TOML file -> merge with env vars -> final configuration

We did so in the Tracker, printing the final config in JSON: