SLING-7167 Adjust READMEs

add uniform header linking to Sling project

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1810855 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/README.md b/README.md
index f7b52cc..815675b 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,5 @@
-Apache Sling JCR Base Bundle
+# Apache Sling JCR Base Bundle
+
+This module is part of the [Apache Sling](https://sling.apache.org) project.
 
 The JCR base bundle provides JCR utility classes.