Add item group monitoring data type framework

Include supported data types for item groups:
--Start event trigger
--Signal event trigger
--A countAtOrAbove condition
--A log_error action

Change-Id: I1ae5ba60e4d9c06155885d52d98a44b31fd73207
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
diff --git a/src/actions.hpp b/src/actions.hpp
new file mode 100644
index 0000000..e1f53ad
--- /dev/null
+++ b/src/actions.hpp
@@ -0,0 +1,27 @@
+#pragma once
+
+#include <phosphor-logging/log.hpp>
+
+namespace phosphor
+{
+namespace dbus
+{
+namespace monitoring
+{
+namespace action
+{
+
+using namespace phosphor::logging;
+
+inline auto log_error(const char* msg)
+{
+    return [=](auto&, auto&)
+    {
+        log<level::ERR>(msg);
+    };
+}
+
+} // namespace action
+} // namespace monitoring
+} // namespace dbus
+} // namespace phosphor