build: General build refactoring

Add vars.mk for variable sharing across makefiles.
Stub and rename example YAML file and template.
  Content to be re-introduced as support is added.
Move generated C++ to a header file.
Add input YAML path option to configure.

Change-Id: Ia06e392e8b120b1e1d8614046064fa432a6f9e18
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/src/monitor.cpp b/src/monitor.cpp
index 9e517fb..2d4d649 100644
--- a/src/monitor.cpp
+++ b/src/monitor.cpp
@@ -98,6 +98,11 @@
     }
 }
 
+const std::vector<
+    std::tuple<
+        std::vector<std::shared_ptr<Event>>,
+        std::vector<Action>>> Monitor::events;
+
 } // namespace monitoring
 } // namespace dbus
 } // namespace phosphor