burn-import: Add optional or configurable logging to generated burn graph

[skewballfox]

Feature description

Something that would be extremely useful in cases like #1877 is some kind of debug information on what operations are being called and what's being passed.

Feature motivation

When refactoring or working on burn-import, bugs became much harder to track once the ONNX graph was parseable. Some bugs only show up when attempting to compile the generated burn graph, and some when actually running it. Catching compile time errors during generation (ONNX graph parsed, burn code generated, compilation fails) is a much harder problem, but debug logging for generated models will make diagnosing runtime issues somewhat straightforward

(Optional) Suggest a Solution

either modify the macro we're using to include something like "if confingurable condition then log info" or add debug logs to all models (which should be excluded from release buillds)

[nathanielsimard]

I think we can use the fusion backend to actually track all burn operations! It's already how we do our graph capture for compilation and works with all burn models, not just the ones imported using burn-import.