Move example file from old wiki into docs.

Summary

The example file located at:

• https://gitlab.rtems.org/rtems/docs/rtems-docs/-/blob/main/user/tracing/examples.rst?ref_type=heads#L34

Needs a new location, it's small why not inline it in the docs so someone could copy and paste?

Here is the file:

• https://gitlab.rtems.org/amar/old-wiki/-/blob/main/Developer/Tracing/Trace_Buffering/fileio-trace.ini?ref_type=heads

Steps to reproduce