[Request] Add trace level

[johnpyp]

As is standard in almost all loggers in other language ecosystems, and mostly standard in modejs, it would be great to add the trace level to finish the log4j-compatible logging levels.

There may be arguments for or against it on principle, but I think for consistency's sake is the strongest reason to add it regardless. Many downstream tools expect all of these levels, and adapters/abstractions over logging do as well.