chore: Add public clouds reference

[patriciareinoso]

Description

We cannot deploy SD-Core in public clouds due to the lack of support of SCTP Load Balancers. This information is added to documentation as a reference.

Checklist:

• [ ] My code follows the style guidelines of this project
• [ ] I have performed a self-review of my own code
• [ ] I have made corresponding changes to the documentation
• [ ] I have added tests that validate the behaviour of the software
• [ ] I validated that new and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules
• [ ] I have bumped the version of the library