Document how to declare oauth parameters in a connector in the connector specification reference

[sherifnada]

Tell us about the problem you're trying to solve

once #5632 is completed, document how to use it in connectors in https://docs.airbyte.io/connector-development/connector-specification-reference

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Are you willing to submit a PR?

Remove this with your answer :-)

[sherifnada]

done in internal document