Java: add Customizations.qll

Author: yo-h

java/ql/src/Customizations.qll

@@ -0,0 +1,12 @@
+/**
+ * Contains customizations to the standard library.
+ *
+ * This module is imported by `java.qll`, so any customizations defined here automatically
+ * apply to all queries.
+ *
+ * Typical examples of customizations include adding new subclasses of abstract classes such as
+ * the `RemoteFlowSource` and `AdditionalTaintStep` classes associated with the security queries
+ * to model frameworks that are not covered by the standard library.
+ */
+
+import java

java/ql/src/java.qll

@@ -1,5 +1,6 @@
 /** Provides all default Java QL imports. */
 
+import Customizations
 import semmle.code.FileSystem
 import semmle.code.Location
 import semmle.code.java.Annotation