[WIP] Improve logging

[CatsDeservePets]

This experimental PR aims to improve lf's logging.

• Add log level and control over them
• Improve existing log messages
• Add more debugging logs in some places

I decided against using slog as it does way more things than we need, doesn't support printf function calls and formats the output in weird way (key=value).
I also decided against introducing another third party library so I just wrote a really simple implementation loosely based on slog.

[CatsDeservePets]

Hey @joelim-work.
I would also like to know, if this is the right direction here.
This is more of a dirty quick hack to look what is possible.

[joelim-work]

Hi @CatsDeservePets,

The current log package only provides basic functionality, but I agree that slog is too much if the use case is just to add log levels. I think the decision to include different log levels depends on user needs - I have never needed it myself, but I am fine with the current implementation if you wish to include it so that it makes your life easier when troubleshooting issues.