Remove I3DEngine CryCommon Interface (#567)

Delete:

- I3DEngine
- Missions
- Time of day
- GameEffectsSystem Gem
- ImageProcessing Gem
- SVOGI Gem
- Various other things that don't do anything now that the legacy renderer has been removed.

Code/CryEngine/CrySystem/LevelSystem/LevelSystem.cpp

@@ -193,10 +193,6 @@ static void UnloadMap([[maybe_unused]] IConsoleCmdArgs* args)
     if (gEnv->pSystem && gEnv->pSystem->GetILevelSystem() && !gEnv->IsEditor())
     {
         gEnv->pSystem->GetILevelSystem()->UnloadLevel();
-        if (gEnv->p3DEngine)
-        {
-            gEnv->p3DEngine->LoadEmptyLevel();
-        }
     }
 }
 
@@ -674,18 +670,6 @@ ILevel* CLevelSystem::LoadLevelInternal(const char* _levelName)
             pSpamDelay->Set(0.0f);
         }
 
-        if (gEnv->p3DEngine)
-        {
-            bool is3DEngineLoaded = gEnv->IsEditor() ? gEnv->p3DEngine->InitLevelForEditor(pLevelInfo->GetPath(), pLevelInfo->m_defaultGameTypeName.c_str())
-                : gEnv->p3DEngine->LoadLevel(pLevelInfo->GetPath(), pLevelInfo->m_defaultGameTypeName.c_str());
-            if (!is3DEngineLoaded)
-            {
-                OnLoadingError(levelName, "3DEngine failed to handle loading the level");
-
-                return 0;
-            }
-        }
-
         // Parse level specific config data.
         AZStd::string const sLevelNameOnly(PathUtil::GetFileName(levelName));
 
@@ -760,14 +744,6 @@ ILevel* CLevelSystem::LoadLevelInternal(const char* _levelName)
 
         gEnv->pSystem->SetSystemGlobalState(ESYSTEM_GLOBAL_STATE_LEVEL_LOAD_START_PRECACHE);
 
-        //////////////////////////////////////////////////////////////////////////
-        // Notify 3D engine that loading finished
-        //////////////////////////////////////////////////////////////////////////
-        if (gEnv->p3DEngine)
-        {
-            gEnv->p3DEngine->PostLoadLevel();
-        }
-
         //////////////////////////////////////////////////////////////////////////
         //////////////////////////////////////////////////////////////////////////
         gEnv->pConsole->SetScrollMax(600 / 2);
@@ -991,18 +967,6 @@ void CLevelSystem::UnloadLevel()
 
     CTimeValue tBegin = gEnv->pTimer->GetAsyncTime();
 
-    I3DEngine* p3DEngine = gEnv->p3DEngine;
-    if (p3DEngine)
-    {
-        IDeferredPhysicsEventManager* pPhysEventManager = p3DEngine->GetDeferredPhysicsEventManager();
-        if (pPhysEventManager)
-        {
-            // clear deferred physics queues before renderer, since we could have jobs running
-            // which access a rendermesh
-            pPhysEventManager->ClearDeferredEvents();
-        }
-    }
-
     //AM: Flush render thread (Flush is not exposed - using EndFrame())
     //We are about to delete resources that could be in use
     if (gEnv->pRenderer)
@@ -1076,25 +1040,10 @@ void CLevelSystem::UnloadLevel()
 
     SAFE_RELEASE(m_pCurrentLevel);
     
-    /*
-        Force Lua garbage collection before p3DEngine->UnloadLevel() and pRenderer->FreeResources(flags) are called.
-        p3DEngine->UnloadLevel() will destroy particle emitters even if they're still referenced by Lua objects that are yet to be collected.
-        (as per comment in 3dEngineLoad.cpp (line 501) - "Force to clean all particles that are left, even if still referenced.").
-        Then, during the next GC cycle, Lua finally cleans up, the particle emitter smart pointers will be pointing to invalid memory).
-        Normally the GC step is triggered at the end of this method (by the ESYSTEM_EVENT_LEVEL_POST_UNLOAD event), which is too late
-        (after the render resources have been purged).
-        This extra GC step takes a few ms more level unload time, which is a small price for fixing nasty crashes.
-        If, however, we wanted to claim it back, we could potentially get rid of the GC step that is triggered by ESYSTEM_EVENT_LEVEL_POST_UNLOAD to break even.
-    */
-
+    // Force Lua garbage collection (may no longer be needed now the legacy renderer has been removed).
+    // Normally the GC step is triggered at the end of this method (by the ESYSTEM_EVENT_LEVEL_POST_UNLOAD event).
     EBUS_EVENT(AZ::ScriptSystemRequestBus, GarbageCollect);
 
-    // Delete engine resources
-    if (p3DEngine)
-    {
-        p3DEngine->UnloadLevel();
-
-    }
     // Force to clean render resources left after deleting all objects and materials.
     IRenderer* pRenderer = gEnv->pRenderer;
     if (pRenderer)