Migrate to log4j2 annotation processor for plugins

[mosche]

Package scanning for log4j2 plugins is long deprecated.
When migrating to 2.25.1 we started seeing deprecation warnings about this, see #132166.

We need to migrate to the recommended approach using the log4j annotation processor.
https://logging.apache.org/log4j/2.x/faq.html#package-scanning

relates to #132035, #132166

[elasticsearchmachine]

Pinging @elastic/es-core-infra (Team:Core/Infra)