Add examples telemetry
# What does this PR do?

This PR adds a function to send telemetry to help us track the examples usage and uses it in the current examples. For now, I've just added in the PyTorch `run_glue.py`, but will paste it in all other examples if you agree with the format/data tracked.
_The documentation is not available anymore as the PR was closed or merged._<|||||>Thanks a lot for working on this @sgugger - that's super useful!