[SYSTEMDS-2870][DOC] Builtin Decision Tree (#1272)
[SYSTEMDS-2870][DOC] Builtin Decision Tree (#1272)

Reference commit: 44e42945
apache/incubator-systemml,apache/incubator-systemml,apache/incubator-systemml,apache/incubator-systemml,apache/incubator-systemml,apache/incubator-systemml