[SEBA-450] (part 2)

Add tox testing support on additional XOS library modules:

- xos-api
- xos-kafka (has no tests)
- xos-migrate (has no tests)
- xos-synchronizer

Change-Id: I98195bc9747971d3515882d517affe058dd86ac5
diff --git a/lib/xos-api/MANIFEST.in b/lib/xos-api/MANIFEST.in
new file mode 100644
index 0000000..223efb9
--- /dev/null
+++ b/lib/xos-api/MANIFEST.in
@@ -0,0 +1,2 @@
+include requirements.txt
+include xosapi/VERSION