Revisit our annotation support now that annotations are available in a native image without a dedicated hint

[snicoll]

GraalVM 22.x has improved so that annotations placed on a method that has an introspecting hint are visible. This makes RuntimeHintsUtils#registerAnnotation largely irrelevant. Remains registerComposableAnnotation that creates a JDK proxy for an annotation we know is going to be synthesized.

This bit is still needed so we need to rework that bit and make it probably a bit more explicit. Current annotations metadata should be removed from the codebase as well.