Extend PulsarIO to support Batch Sources. This pr implements PIP-65 (#7090)

* Extennd PulsarIO to support Batch Sources. This pr implements PIP-65

* Added license

* Fix headers

Co-authored-by: Sanjeev Kulkarni <sanjeevk@splunk.com>
diff --git a/pulsar-io/pom.xml b/pulsar-io/pom.xml
index 2e875e4..ccf80e0 100644
--- a/pulsar-io/pom.xml
+++ b/pulsar-io/pom.xml
@@ -33,6 +33,9 @@
 
   <modules>
     <module>core</module>
+    <module>batch</module>
+    <module>batch-discovery-triggerers</module>
+    <module>batch-data-generator</module>
     <module>common</module>
     <module>docs</module>
     <module>aws</module>