Source Salesforce: declare oauth parameters in spec

[sherifnada]

Tell us about the problem you're trying to solve

blocked on #5632

Describe the solution you’d like

A clear and concise description of what you want to see happen, or the change you would like to see

Describe the alternative you’ve considered or used

A clear and concise description of any alternative solutions or features you've considered or are using today.

Additional context

Add any other context or screenshots about the feature request here.

Are you willing to submit a PR?

Remove this with your answer :-)