Initial support for event callbacks

Add parser support for template rendering of events.
Also defines the EventBase and Event classes.
EventBase is parent of Event.

Change-Id: I6b07b415acf510a8437529095bd489c0af73ddf5
Signed-off-by: Ratan Gupta <ratagupt@in.ibm.com>
diff --git a/src/templates/event.mako.cpp b/src/templates/event.mako.cpp
new file mode 100644
index 0000000..e5ac850
--- /dev/null
+++ b/src/templates/event.mako.cpp
@@ -0,0 +1,2 @@
+std::make_unique<Event<${c.datatype}>>("${c.eventName}"s, "${c.eventMessage}"s,
+${indent(1)}ConfigPropertyIndicies::get()[${c.instances}])\
diff --git a/src/templates/generated.mako.hpp b/src/templates/generated.mako.hpp
index 740acfa..4a5b87c 100644
--- a/src/templates/generated.mako.hpp
+++ b/src/templates/generated.mako.hpp
@@ -14,6 +14,7 @@
 #include "propertywatchimpl.hpp"
 #include "resolve_errors.hpp"
 #include "sdbusplus.hpp"
+#include "event.hpp"
 #include "sdevent.hpp"
 
 using namespace std::string_literals;