Doc: Add section `How to connect to consul-connect enabled services`

[pdmthorsrud]

Feature description

This issue came up in vagrant-hashistack, and I realise we have no documentation on how to do this is in new modules (only the modules we have created ourselves)

but even that is very lackluster. We need some actual documentation on how to get access to the consul-connect enabled services.

Why is it needed?

Easier usage for users

Suggestion(s)/solution(s) [Optional]

Definition of done

A section in README.md, getting_started_modules.md or getting_started_vagrantbox.md. I'm thinking maybe the vagrantbox doc is the most appropriate, but that's up for discussion :D

Example on how you open access to the services: https://github.com/fredrikhgrelland/terraform-nomad-minio/blob/master/Makefile#L77-L79 https://github.com/fredrikhgrelland/terraform-nomad-minio#verifying-setup

Checklist (after created issue)

• [x] Added label(s)
• [ ] Added to project
• [ ] Added to milestone

[fredrikhgrelland]

@pdmthorsrud Please back port envoy pattern here.