Refactor CoreCLR runtime into explicit dotnet api instead of mocking mono api

Required by platforms that will use mono under the hood for .Net 7
New `USE_CSHARP` define for C# ability
Engine doesn't use `mono_*` apis directly but via MCore/MClass/MMethod/ apis

Source/Engine/Scripting/Internal/MainThreadManagedInvokeAction.cpp

@@ -0,0 +1,122 @@
+// Copyright (c) 2012-2023 Wojciech Figat. All rights reserved.
+
+#include "MainThreadManagedInvokeAction.h"
+#include "Engine/Threading/Threading.h"
+#include "Engine/Scripting/ScriptingCalls.h"
+#include "Engine/Scripting/ManagedCLR/MException.h"
+
+MainThreadManagedInvokeAction* MainThreadManagedInvokeAction::Invoke(MMethod* method, MObject* instance, LogType exceptionLevel)
+{
+    ASSERT_LOW_LAYER(method != nullptr);
+
+    if (IsInMainThread())
+    {
+        MainThreadManagedInvokeAction task(instance, method, exceptionLevel);
+        task.Run();
+        return nullptr;
+    }
+    else
+    {
+        auto task = New<MainThreadManagedInvokeAction>(instance, method, exceptionLevel);
+        task->Start();
+        return task;
+    }
+}
+
+MainThreadManagedInvokeAction* MainThreadManagedInvokeAction::Invoke(MMethod* method, ParamsBuilder& params, MObject* instance, LogType exceptionLevel)
+{
+    ASSERT_LOW_LAYER(method != nullptr);
+
+    if (IsInMainThread())
+    {
+        MainThreadManagedInvokeAction task(instance, method, exceptionLevel, params);
+        task.Run();
+        return nullptr;
+    }
+    else
+    {
+        auto task = New<MainThreadManagedInvokeAction>(instance, method, exceptionLevel, params);
+        task->Start();
+        return task;
+    }
+}
+
+MainThreadManagedInvokeAction* MainThreadManagedInvokeAction::Invoke(void* methodThunk, ParamsBuilder& params, LogType exceptionLevel)
+{
+    ASSERT_LOW_LAYER(methodThunk != nullptr);
+
+    if (IsInMainThread())
+    {
+        MainThreadManagedInvokeAction task(methodThunk, exceptionLevel, params);
+        task.Run();
+        return nullptr;
+    }
+    else
+    {
+        auto task = New<MainThreadManagedInvokeAction>(methodThunk, exceptionLevel, params);
+        task->Start();
+        return task;
+    }
+}
+
+void MainThreadManagedInvokeAction::InvokeNow(MMethod* method, ParamsBuilder& params, MObject* instance, LogType exceptionLevel)
+{
+    ASSERT_LOW_LAYER(method != nullptr);
+
+    void* paramsData[8];
+    params.GetParams(paramsData);
+
+    MObject* exception = nullptr;
+    method->Invoke(instance, paramsData, &exception);
+    if (exception)
+    {
+        MException ex(exception);
+        ex.Log(exceptionLevel, TEXT("Main thread action"));
+    }
+}
+
+bool MainThreadManagedInvokeAction::Run()
+{
+    bool failed = false;
+
+    void* paramsData[8];
+    _params.GetParams(paramsData);
+
+    MObject* exception = nullptr;
+    if (_method)
+    {
+        _method->Invoke(_instance, paramsData, &exception);
+    }
+    else if (_methodThunk)
+    {
+        switch (_params.Count)
+        {
+        case 0:
+            ((Thunk_Void_0)_methodThunk)(&exception);
+            break;
+        case 1:
+            ((Thunk_Void_1)_methodThunk)(paramsData[0], &exception);
+            break;
+        case 2:
+            ((Thunk_Void_2)_methodThunk)(paramsData[0], paramsData[1], &exception);
+            break;
+        case 3:
+            ((Thunk_Void_3)_methodThunk)(paramsData[0], paramsData[1], paramsData[2], &exception);
+            break;
+        case 4:
+            ((Thunk_Void_4)_methodThunk)(paramsData[0], paramsData[1], paramsData[2], paramsData[3], &exception);
+            break;
+        default:
+            exception = nullptr;
+            CRASH;
+        }
+    }
+    if (exception)
+    {
+        failed = true;
+        MException ex(exception);
+        ex.Log(_exceptionLevel, TEXT("Main thread action"));
+    }
+
+    return failed;
+}