feat: cater for multiple registry entries in a .npmrc file

[johnnyreilly]

PR Checklist

• Addresses an existing open issue: fixes 🚀 Feature: allow for multiple registry entries in a .npmrc #32
• That issue was marked as status: accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

This PR amends azdo-npm-auth to cater for a number of registry entries in the same project .npmrc file. Something like this:

registry=https://pkgs.dev.azure.com/johnnyreilly/_packaging/organization-feed-name/npm/registry/
@myorg:registry=https://pkgs.dev.azure.com/johnnyreilly/project-name1/_packaging/project-feed-name/npm/registry/
@myorg-other:registry=https://pkgs.dev.azure.com/johnnyreilly/another-project-name/_packaging/different-project-feed-name/npm/registry/
                        
always-auth=true