Proposed changes

Add information about which ports are required by thin-edge.io to communicate to each cloud.

This work was spawned from a debug session which a customer which was using thin-edge.io behind a strictly controlled network and firewall rules needed to be created before thin-edge.io could connect to the appropriate cloud.

An additional "Debug section" could also be added, however it was decided it would be a better UX to create built-in command to do the connectivity checks like "can I reach the network" to give clear guidance on how to check these scenearios.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (general improvements like code refactoring that doesn't explicitly fix a bug or add any new functionality)
• Documentation Update (if none of the other choices apply)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Paste Link to the issue

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA (in all commits with git commit -s)
• I ran cargo fmt as mentioned in CODING_GUIDELINES
• I used cargo clippy as mentioned in CODING_GUIDELINES
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments