Add docs for connecting to Azure DevOps as a code host

Created by: dadlerj

From a user

I'm trying to configure repos from Azure DevOps using SSH authentication.

I tried following these instructions: https://docs.sourcegraph.com/admin/external_service/other

I'm a little foggy though. For starters, I don't know the SSH port number that Azure DevOps uses.

Do you have any more specific instructions specially for Azure DevOps?

Based on searching online, it looks like Azure DevOps only supports port 22 for SSH access, so no port number is required. References:

• https://developercommunity.visualstudio.com/idea/668359/ssh-server-for-git-on-port-443.html
• https://docs.microsoft.com/en-us/azure/devops/repos/git/use-ssh-keys-to-authenticate?view=azure-devops&tabs=current-page