Make loadable implement GSON serializers

Just saves another class creation a this one has all the info needed

src/main/java/slimeknights/mantle/data/loadable/Loadable.java

@@ -1,7 +1,12 @@
 package slimeknights.mantle.data.loadable;
 
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
 import com.google.gson.JsonSyntaxException;
 import io.netty.handler.codec.DecoderException;
 import io.netty.handler.codec.EncoderException;
@@ -14,14 +19,15 @@
 import slimeknights.mantle.data.loadable.mapping.MappedLoadable;
 import slimeknights.mantle.data.loadable.mapping.SetLoadable;
 
+import java.lang.reflect.Type;
 import java.util.List;
 import java.util.Set;
 import java.util.function.BiFunction;
 import java.util.function.Function;
 
 /** Interface for a generic loadable object */
 @SuppressWarnings("unused")  // API
-public interface Loadable<T> {
+public interface Loadable<T> extends JsonDeserializer<T>, JsonSerializer<T> {
   /** Deserializes the object from json */
   T convert(JsonElement element, String key) throws JsonSyntaxException;
 
@@ -48,6 +54,19 @@ default T getAndDeserialize(JsonObject parent, String key) {
   void toNetwork(T object, FriendlyByteBuf buffer) throws EncoderException;
 
 
+  /* GSON methods, lets us easily use loadables with GSON adapters */
+
+  @Override
+  default T deserialize(JsonElement json, Type type, JsonDeserializationContext context) throws JsonParseException {
+    return convert(json, type.getTypeName());
+  }
+
+  @Override
+  default JsonElement serialize(T object, Type type, JsonSerializationContext context) {
+    return serialize(object);
+  }
+
+
   /* Fields */
 
   /** Creates a required field from this loadable */