Utils: Make aspect settings access implicit

Generally, aspects should use fromMap/toMap, but some older pages
use {from,to}Settings with always the same ICore::settings().

To make that less intrusive on the user code side, make that globally
implicit.

Task-number: QTCREATORBUG-29167
Change-Id: I29a8e23a31eb8061bb143e93931a07c6741eb7f9
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp

@@ -598,7 +598,7 @@ void CMakeBuildSettingsWidget::reconfigureWithInitialParameters()
         QMessageBox::Yes | QMessageBox::No,
         QMessageBox::Yes);
 
-    settings->writeSettings(Core::ICore::settings());
+    settings->writeSettings();
 
     if (reply != QMessageBox::Yes) {
         return;