Services: Use default constructors/destructors

https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#cother-other-default-operation-rules

"The compiler is more likely to get the default semantics right and
you cannot implement these functions better than the compiler."

Userland/Services/WindowServer/EventLoop.h

@@ -20,7 +20,7 @@ class ConnectionFromClient;
 class EventLoop {
 public:
     EventLoop();
-    virtual ~EventLoop();
+    virtual ~EventLoop() = default;
 
     int exec() { return m_event_loop.exec(); }