refactor: Hide auth behind one URL

[PathumN99]

#7818

• Refactoring specific API endpoints to use node-fetch calls instead of proxying from the gateway to the auth microservice.
• Replaced AUTH_URL usages in client & login apps with API_GATEWAY_URL/api/auth
• Removed Traefik configurations that exposes auth to the public internet (#329 in country-config)

[github-actions]

Oops! Looks like you forgot to update the changelog. When updating CHANGELOG.md, please consider the following:

• Changelog is read by country implementors who might not always be familiar with all technical details of OpenCRVS. Keep language high-level, user friendly and avoid technical references to internals.
• Answer "What's new?", "Why was the change made?" and "Why should I care?" for each change.
• If it's a breaking change, include a migration guide answering "What do I need to do to upgrade?".

[naftis]

Looks good so far! 👍

[naftis]

I'm closing this as it's not currently a priority. I'll get back to this PR when we prioritize it for 1.7 or 1.8.