feat(config-api): enhanced security for config-api endpoints

To strength security of endpoints making following changes
- Enhance CORS Validation and Security Checks
- Enhance Content Security Policy (CSP)

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### Description

- Development target issue
- Validating the Origin against an explicit allow list
- Adding response headers

- Implementation Details

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### Prepare

- [ ] Read contribution guidelines
- [ ] Read license information

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### Identified code changes

- [ ] task 1
- [ ] task 2
- [ ] task 3

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### Test cases and code coverage

- [ ] Write unit test to cover added/changed code
- [ ] Update integration tests to cover added/changed code

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### Document the changes

- [ ] task for updating user guides if needed
- [ ] task for updating installation and configuration guides if needed
- [ ] task for updating developer documentation if needed
- [ ] task for updating technical documentation if needed