.clang-format: disable formatting app and file templates

Application and file templates are used by regular KDevelop users. So we
should allow template authors to define formatting rather than enforce
KDevelop's formatting style.

Plus the template syntax is extended C++, so there is breaking diff like
this in app_templates/cpp/CMake/cmake_kdevplugin/src/%{APPNAMELC}.cpp:
-K_PLUGIN_FACTORY_WITH_JSON(%{APPNAMEID}Factory, "%{APPNAMELC}.json", registerPlugin<%{APPNAMEID}>(); )
+K_PLUGIN_FACTORY_WITH_JSON(% {APPNAMEID} Factory, "%{APPNAMELC}.json", registerPlugin<% {APPNAMEID}>();)

-%{APPNAMEID}::%{APPNAMEID}(QObject *parent, const QVariantList& args)
+    %
+{
+    APPNAMEID
+}
+::
+        % {APPNAMEID}(QObject* parent, const QVariantList& args)
     : KDevelop::IPlugin(QStringLiteral("%{APPNAMELC}"), parent)
 {
     Q_UNUSED(args);

-    qCDebug(PLUGIN_%{APPNAMEUC}) << "Hello world, my plugin is loaded!";
+    qCDebug(PLUGIN_ % {APPNAMEUC}) << "Hello world, my plugin is loaded!";
 }