Improve logging

[nikipapadatou]

This is a task that includes everything that is not already reported in other relevant logging issues.

We are called to improve the entire logging in our codebase. At the moment there are misleading error messages, log levels are not indicative to the severity of an event and log messages do not indicate what the issue could be. More specifically we should focus on the following:=

• Consider where logging is missing (especially on critical cases) and enhance it.
• Assign to each log case the appropriate logging level.
• We should always include indicative log messages, with all the information that will be relevant either to the node operator or the developer. Avoid generic messages that are difficult to identify what the issue might be.