docs(aws): fix broken links

[ojacques]

Description

Fix broken links for Amazon Security Hub:

• In report.md, link to ASFF / Security Hub tutorial
• In aws-security-hub.md tutorial, fix image link and resizing thanks to attr_list
• In aws-security-hub.md tutorial, make link to AWS blog clickable

Before:

After:

Related issues

• Not applicable: simple doc fix.

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).

[CLAassistant]

All committers have signed the CLA.

[knqyf263]

Thanks!