Debugger: Allow GDB/LLDB DAP debugger as native C++ debugger

This would allow manual registration of a GDB/LLDB DAP debugger from a
CMake configure preset as follows:

```
  "vendor": {
      "qt.io/QtCreator/1.0": {
        "debugger": {
          "DisplayName": "LLDB Dap 18.1.7 Debugger",
          "Abis": ["arm-darwin-generic-mach_o-64bit"],
          "Binary": "/Users/cristian/llvm/clang/bin/lldb-dap",
          "EngineType": 1024,
          "Version": "18.1.7"
        }
      }
    }
```

This way I can configure a project with a toolchain that uses a DAP
debugger (not every gdb/lldb has python bindings) and have debugging
working out of the box.

Change-Id: Id9bff26b6544b7af99caccb18cdbe0edb334218a
Reviewed-by: Artem Sokolovskii <artem.sokolovskii@qt.io>
Reviewed-by: hjk <hjk@qt.io>

src/plugins/debugger/debuggeritem.cpp

@@ -271,6 +271,10 @@ QString DebuggerItem::engineTypeName() const
         return QLatin1String("CDB");
     case LldbEngineType:
         return QLatin1String("LLDB");
+    case GdbDapEngineType:
+        return QLatin1String("GDB DAP");
+    case LldbDapEngineType:
+        return QLatin1String("LLDB DAP");
     case UvscEngineType:
         return QLatin1String("UVSC");
     default: