Exclude Netty's reflection configuration files

These are causing warnigns during native image compilation as they try
to access classes that are not on the
classpath (e.g. `net.jpountz.lz4.LZ4Exception`).

Closes #29413

extensions/netty/deployment/src/main/java/io/quarkus/netty/deployment/NettyOverrideMetadata.java

@@ -0,0 +1,15 @@
+package io.quarkus.netty.deployment;
+
+import io.quarkus.deployment.annotations.BuildStep;
+import io.quarkus.deployment.builditem.nativeimage.ExcludeConfigBuildItem;
+
+public class NettyOverrideMetadata {
+
+    static final String NETTY_JAR_MATCH_REGEX = "io\\.netty\\.netty-(codec|handler)";
+    static final String NETTY_REFLECT_CONFIG_MATCH_REGEX = "/META-INF/native-image/io\\.netty/netty-(codec|handler)/generated/handlers/reflect-config\\.json";
+
+    @BuildStep
+    ExcludeConfigBuildItem excludeNettyDirectives() {
+        return new ExcludeConfigBuildItem(NETTY_JAR_MATCH_REGEX, NETTY_REFLECT_CONFIG_MATCH_REGEX);
+    }
+}