add default implementation to early register entrypoint so users don'…

…t need to implement both entrypoints even if they only need the late ("main") one

common/src/api/java/net/caffeinemc/mods/sodium/api/config/ConfigEntryPoint.java

@@ -3,7 +3,8 @@
 import net.caffeinemc.mods.sodium.api.config.structure.ConfigBuilder;
 
 public interface ConfigEntryPoint {
-    void registerConfigEarly(ConfigBuilder builder);
+    default void registerConfigEarly(ConfigBuilder builder) {
+    };
 
     void registerConfigLate(ConfigBuilder builder);
 }