internal: new shared_ptr and weak_ptr implementation (#5883)

moves std::shared_ptrs to a new implementation

Advantages:
- you can dereference a weak_ptr directly. This will obviously segfault on a nullptr deref if it's expired.
   - this is useful to avoid the .lock() hell where we are 100% sure the pointer _should_ be valid. (and if it isn't, it should throw.)
- weak_ptrs are still valid while the SP is being destroyed.
   - reasoning: while an object (e.g. CWindow) is being destroyed, its `weak_ptr self` should be accessible (the sp is still alive, and so is CWindow), but it's not because by stl it's already expired (to prevent resurrection)
   - this impl solves it differently. w_p is expired, but can still be dereferenced and used. Creating `s_p`s is not possible anymore, though.
   - this is useful in destructors and callbacks.

src/managers/eventLoop/EventLoopManager.cpp

@@ -38,12 +38,12 @@ void CEventLoopManager::onTimerFire() {
     nudgeTimers();
 }
 
-void CEventLoopManager::addTimer(std::shared_ptr<CEventLoopTimer> timer) {
+void CEventLoopManager::addTimer(SP<CEventLoopTimer> timer) {
     m_sTimers.timers.push_back(timer);
     nudgeTimers();
 }
 
-void CEventLoopManager::removeTimer(std::shared_ptr<CEventLoopTimer> timer) {
+void CEventLoopManager::removeTimer(SP<CEventLoopTimer> timer) {
     std::erase_if(m_sTimers.timers, [timer](const auto& t) { return timer == t; });
     nudgeTimers();
 }