Micrometer Prometheus client v1.0 breaking changes

[brunobat]

TODO:

• I still need to come up with better examples for the changes.
• Release nr. for the new extension.

[github-actions]

🎊 PR Preview 020309c has been successfully built and deployed to https://quarkus-site-pr-2340-preview.surge.sh

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[Copilot]

Pull Request Overview

This PR introduces a new documentation post detailing the migration paths and breaking changes resulting from the switch to Prometheus client v1 in the Micrometer registry.

• Introduces a new post explaining upgrade options and dependency changes
• Details specific changes to metrics naming and API usage

[brunobat]

There is a plan change:

1. Keep current extension as is until Quarkus 4.0 (whenever that happens)
2. Create a new extension called quarkus-micrometer-registry-prometheus-v1 now
3. Delete current quarkus-micrometer-registry-prometheuson Quarkus 4.0. Provide alternative on Quarkiverse.
4. Refactor: Stramline the main extension (quarkus-micrometer) and quarkus-micrometer-registry-prometheus-v1 to remove outdated code on Quarkus 4.0.
5. On the next LTS it would be good to mark for deprecation the old registry and support the new one.

Will re-write the blog to reflect that.

[brunobat]

Re-wrote the post according to the new plan and zulip coments.
I still need to come up with better examples for the changes.
Will finish when I know when we will release the new extension.