Switch internal instrumentation macros to use profiling crate instead, allowing instrumentation with different profilers

[teddemunnik]

Hey! I am not sure if this is something that's been considered before and decided against (I couldn't find any PR's or issues).

This change removes the internal profiling macros in library crates and the puffin feature and replaces it with similar functions in the profiling crate. This crate provides a layer of abstraction over various profiler instrumentation crates and allows library users to pick their favorite (supported) profiler.

An additional benefit for puffin users is that dependencies of egui are included in the instrumentation output too (mainly wgpu which uses the profiling crate), so more details might be available when profiling.

A breaking change is that instead of using the puffin feature on egui, users that want to profile the crate with puffin instead have to enable the profile-with-puffin feature on the profiling crate. Similarly they could instead choose to use profile-with-tracy etc.

I tried to add a 'tracy' feature to egui_demo_app in order to showcase , however the /scripts/check.sh currently breaks on mutually exclusive features (which this introduces), so I decided against including it for the initial PR. I'm happy to iterate more on this if there is interest in taking this PR though.

Screenshot showing the additional info for wgpu now available when using puffin