docs: add details to curl command guide

[ossdhaval]

Prepare

• Read PR guidelines
• Read license information

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Description

• added instructions to create minimal client using CURL
• replaced sections on getting scopes and grant types with more inclusive section of getting client information
• fixed typo in command for getting access token
• added expected responses

Target issue

closes #issue-number-here

Implementation Details

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Test and Document the changes

• Static code analysis has been run locally and issues have been fixed
• Relevant unit and integration tests have been added/updated
• Relevant documentation has been updated if any (i.e. user guides, installation and configuration guides, technical design docs etc)