[examples template] added max_sample args and metrics changes

[bhadreshpsavani]

What does this PR do?

This PR adds the same as #10551 and #10436 to the cookie-cutter template.

Fixes #10423

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review:

@stas00

[stas00]

Looks good, @bhadreshpsavani!

Sorry, I sent you to the wrong part of the cookie-cutter, originally. I should have sent you here instead:
https://github.com/huggingface/transformers/tree/master/templates/adding_a_new_example_script

But I run it and the autogenerated code based on your edits runs just fine.

So all is good.

Thank you!

[bhadreshpsavani]

Ya @stas00,
Actually I figured that and tested visually with the example tamplate not the model template

[sgugger]

Looks good to me, thanks for adding this in the template as well!