Description

Disabled postfix-sasl jail and added a note to the documentation.

Fixes #4336

Type of change

• Improvement (non-breaking change that does improve existing functionality)
• This change requires a documentation update

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (README.md or the documentation under docs/)
• If necessary, I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have added information about changes made in this PR to CHANGELOG.md