[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.