chore: config dtk animations

set/unset `D_DTK_DISABLE_ANIMATIONS` according to the dconfig

src/kernel/dguiapplicationhelper.cpp

@@ -115,6 +115,7 @@ Q_GLOBAL_STATIC(DFontManager, _globalFM)
 #define WINDOW_THEME_KEY "_d_platform_theme"
 
 #define APP_THEME_TYPE "themeType"
+#define DTK_ENABLE_ANIMATIONS "enableDtkAnimations"
 Q_GLOBAL_STATIC_WITH_ARGS(DTK_CORE_NAMESPACE::DConfig, _d_dconfig, ("org.deepin.dtk.preference"));
 
 /*!
@@ -286,6 +287,17 @@ void DGuiApplicationHelperPrivate::initApplication(QGuiApplication *app)
 
     systemSizeMode = static_cast<DGuiApplicationHelper::SizeMode>(systemTheme->sizeMode());
     q->connect(systemTheme, SIGNAL(sizeModeChanged(int)), q, SLOT(_q_sizeModeChanged(int)));
+
+    if (_d_dconfig.exists())
+        return;
+
+    const QLatin1String env("D_DTK_DISABLE_ANIMATIONS");
+    const bool shouldEnable = _d_dconfig->value(DTK_ENABLE_ANIMATIONS, false).toBool();
+    const bool isEnable = !qEnvironmentVariableIsSet(env.data());
+
+    if (shouldEnable ^ isEnable) {
+        shouldEnable ? qunsetenv(env.data()) : qputenv(env.data(), "1");
+    }
 }
 
 void DGuiApplicationHelperPrivate::staticInitApplication()
@@ -529,7 +541,6 @@ DGuiApplicationHelper::DGuiApplicationHelper()
     : QObject(nullptr)
     , DObject(*new DGuiApplicationHelperPrivate(this))
 {
-
 }
 
 void DGuiApplicationHelper::initialize()