Restructured javadocs build to make groupings more manageable in the light of mavan-javadoc-plugin's silly treatment of package lists.

Change-Id: I771db3399bf8f0463927b2720ff43f862d7f2d68
diff --git a/docs/external-apis b/docs/external-apis
new file mode 100644
index 0000000..4e18664
--- /dev/null
+++ b/docs/external-apis
@@ -0,0 +1,3 @@
+org.onosproject
+org.onosproject.*
+org.onosproject.rest
\ No newline at end of file