Swap the API packages

The new one is now built for the api jar and the old one is now internal.
It will slowly be moved around to sane places within the internal code. Most
of the features provided in the old "api" are addon specific features which
will generally rely on the main jar anyways. The new API will be specific
to compatibility features, such as blacklists, recipes, and value modification.

src/main/java/WayofTime/bloodmagic/api/BloodMagicPlugin.java

@@ -0,0 +1,12 @@
+package WayofTime.bloodmagic.api;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.TYPE)
+public @interface BloodMagicPlugin {
+
+}