Rename event-bus module to event-bus-core, add event-bus-ap module

event-bus is now a parent project containing the two modules
event-bus-core (the previous event-bus) and event-bus-ap (annotation
processor).

The version of the parent project (and thus that of the modules) has
been bumped to 1.0.0, as this change breaks compatibility with previous
versions due to the different artifact, module and package names.

event-bus-core/src/test/java/dev/kske/eventbus/core/CancelTest.java

@@ -1,4 +1,4 @@
-package dev.kske.eventbus;
+package dev.kske.eventbus.core;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 

event-bus-core/src/test/java/dev/kske/eventbus/core/DispatchTest.java

@@ -1,4 +1,4 @@
-package dev.kske.eventbus;
+package dev.kske.eventbus.core;
 
 import static org.junit.jupiter.api.Assertions.*;
 

event-bus-core/src/test/java/dev/kske/eventbus/core/SimpleEvent.java

@@ -1,4 +1,4 @@
-package dev.kske.eventbus;
+package dev.kske.eventbus.core;
 
 /**
  * A simple event for testing purposes.

event-bus-core/src/test/java/dev/kske/eventbus/core/SimpleEventSub.java

@@ -1,4 +1,4 @@
-package dev.kske.eventbus;
+package dev.kske.eventbus.core;
 
 /**
  * Subclass of {@link SimpleEvent} for testing purposes.