Oauth OIDC CCloud producer example

[pranavrth]

Continuation of #1593 as the owner of the PR left the org.

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✅ pranavrth
❌ sarwarbhuiyan
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[emasab]

Suggested change

	# This uses OAuth client credentials grant:
	# https://www.oauth.com/oauth2-servers/access-tokens/client-credentials/
	# where client_id and client_secret are passed as HTTP Authorization header
	# This uses OAuth client credentials grant:
	# https://www.oauth.com/oauth2-servers/access-tokens/client-credentials/
	# where client_id and client_secret are passed as HTTP Authorization header
	# with the OIDC method and doesn't need to set a `oauth_cb` to obtain the token,
	# but, given it's using cURL for http requests, when using bundled librdkafka on non RHEL based distros,
	# currently it needs to provide CA bundle at a specific path, that is `/etc/pki/tls/certs/ca-bundle.crt`.

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[emasab]

LGTM! Thanks