Add a `burn-profiler` crate to evaluate performances

Feature description

Besed on the bevy-log crate, the burn-profiler crate must be able to evaluate function performances and detect where the hotspots could be localized. The crate should also provide APIs to allow spans creation. A span is used to measure specific code portions and bevy profiling section can be an example:

{
  // creates a span and starts the timer
  let my_span = info_span!("span_name", name = "span_name").entered();
  do_something_here();
} // my_span is dropped here ... this stops the timer

The crate should also implement APIs to interact with external profilers such as the Tracy Profiler Trace.

Roadmap:

• 1. Add burn-profiler spans APIs
• 2. Document how to use these APIs in the Contributor book
• 3. Verify if those APIs work in an async context
• 4. Evaluate whether those APIs can work in a no_std environment

Feature motivation

Evaluating whether there are functions and methods which consumes a great amount of resources in terms of memory and computation