Logging

We are using tracing to implement logging in our kernel.

So, you can use trace!, debug!, info!, warn!, and error! macros to log messages.

Currently, we don't support spans yet.

As of now, the level of tracing is hardcoded to ignore trace! and debug! messages, but we want to add kernel command-line arguments to change the level of tracing.

The logs are also saved into a file that is replaced every time the kernel is booted. The file is /kernel.log.