fix headings and reorg

[lbadenhop]

Thank you for your contribution to the Axway-Open-Docs repo.

Describe the changes

Enter a brief description of your changes here to communicate to the maintainers what you changed and why.

Checklist for contributors

Before submitting this PR, please make sure:

• You have read the contribution guidelines
• You have signed the Axway CLA
• You have verified the technical accuracy of your change
• You have verified that your change does not expose any sensitive information (passwords, keys, etc.)
• You have followed the Markdown guidelines (unless this is is a Netlify CMS contribution)

Put an x in the boxes that apply. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your change.

Checklist for approvers

This section is to be filled out by project maintainers only.

Before approving this PR, please make sure it:

• Does not have conflicts with the base branch
• Is clear and complete
• Is believed to be accurate (technical accuracy to be checked with an SME for PRs originating from outside R&D)
• Follows Axway style
• Follows Markdown guidelines
• Follows best practices
• Does not contain typos, grammatical errors, etc.
• Does not expose any sensitive information
• Passes the Markdown linter rules (automated via CI check)
• Does not contain broken links
• Is discoverable and navigable

Checklist for mergers

This section is to be filled out by project maintainers only.

Before merging this PR, please make sure:

• You have applied a size label (unless this work is tracked in the ReadMeFirst JIRA project)
• You have applied a production label if this needs a manual push to Zoomin
• You have added it to the correct GitHub project
• You have added it to the correct Sprint milestone
• You have appended a fixes line to this description if this PR fixes a specific GitHub issue
• You have added a new collection to Netlify CMS config (static/admin/config.js) if required (new doc sections)
• You have updated the Zoomin classification file if required (new AMPC topics)

[docsbuilder]

✅ Deploy preview is ready!

Name	Link
🔨 Latest commit	ffd9879
😎 Deploy preview	http://PR-66.open-banking-docs.opendocs-builder.pcloud.axway.int

[lbadenhop]

@axway-akb - I'll update the classification file once the PR is approved. This will only allow "customer-only" to view the security guide content.

[axway-akb]

Looks good.