Move EventScheduler out to its own file to avoid circular dependency

Author: yyzhong-g

src/app/BUILD.gn

@@ -432,6 +432,7 @@ static_library("app") {
     "CommandResponseSender.cpp",
     "EventLogging.h",
     "EventManagement.cpp",
+    "EventManagement.h",
     "FailSafeContext.cpp",
     "FailSafeContext.h",
     "GenericEventManagementTestEventTriggerHandler.cpp",

src/app/EventManagement.h

@@ -191,18 +191,6 @@ struct LogStorageResources
         PriorityLevel::Invalid; // Log priority level associated with the resources provided in this structure.
 };
 
-/**
- * @brief
- *  A EventScheduler to schedule deliveries of events.
- */
-
-class EventScheduler
-{
-public:
-    virtual ~EventScheduler()                                                                   = default;
-    CHIP_ERROR virtual ScheduleEventDelivery(ConcreteEventPath & aPath, uint32_t aBytesWritten) = 0;
-};
-
 /**
  * @brief
  *   A class for managing the in memory event logs.  See documentation at the