feat(microservice): add TLS over TCP support

[Flusinerd]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/docs.nestjs.com/blob/master/CONTRIBUTING.md

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Docs
• Other... Please describe:

What is the current behavior?

No docs for TLS over TCP support.

Issue Number: 6745
Pull Request: 7516

What is the new behavior?

Added TLS support section to Basics page in Microservice section.

Does this PR introduce a breaking change?

• Yes
• No

Other information

[elucidsoft]

Is this going to get committed?

[Flusinerd]

@elucidsoft it's still wip. I don't have time atm to work on this. Check nestjs/nest#7516

[Tony133]

Suggested change

[Tony133]

I've just pointed out a few small things to change, but otherwise it looks like a good addition to the documentation. 👍