allow to listen on unix domain sockets

[kristofvandam]

Pull Request

What does this PR do?

• adds the ability to set a Unix domein socket as host_addr
• show the protocol used on startup

reason

It's easier to create multiple instances and create (nginx for example) vhosts for them

PR checklist

Please check if your PR fulfills the following requirements:

• [ x ] Does this PR fix an existing issue, or have you listed the changes applied in the PR description (and why they are needed)?
• [ x ] Have you read the contributing guidelines?
• [ x ] Have you made sure that the title is accurate and descriptive of the changes?

Thank you so much for contributing to Meilisearch!

[Kerollmops]

Hey @kristofvandam 👋 Thank you very much for your contribution. Have you tested these changes, already?

[kristofvandam]

Hi, not yet, i don't have any Windows environment in my reach 🫤 i'm not familiar with rust either, i just thought it was an easy fix and gave it a go tbh 😁