Refactoring logs #1

[israelboudoux]

• We will stick to the pino logging library (https://www.npmjs.com/package/pino), just to follow what nightfall-sdk is using, then it will become our default library. We need to configure it;
• The logging level and other possible definitions will be defined via environment variables (See https://github.com/maticnetwork/nightfall-sdk/blob/master/libs/utils/logger.ts);
• The default format for logs is JSON, then this should be configured accordingly in the library;
• The logs can use pretty JSON when using a local environment, just to facilitate reading the logs during development. We can do this via some environment variable;
• The output should be directed to stdout/stderr - I think we are already doing it!;
• Change all logs calls that aren't the default ones (trace, debug, info, warn, error) to debug (e.g. silly);
• Test to verify the correct behavior of the applications and to assert that the work is completed thoroughly.

In another moment we will refactor the log messages and add information that could be valuable for troubleshooting (See #847)