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/SessionLockManager.cpp

@@ -5,12 +5,12 @@
 #include "../protocols/SessionLock.hpp"
 
 SSessionLockSurface::SSessionLockSurface(SP<CSessionLockSurface> surface_) : surface(surface_) {
-    pWlrSurface = surface.lock()->surface();
+    pWlrSurface = surface->surface();
 
     listeners.map = surface_->events.map.registerListener([this](std::any data) {
         mapped = true;
 
-        g_pCompositor->focusSurface(surface.lock()->surface());
+        g_pCompositor->focusSurface(surface->surface());
 
         const auto PMONITOR = g_pCompositor->getMonitorFromID(iMonitorID);
 
@@ -124,7 +124,7 @@ bool CSessionLockManager::isSurfaceSessionLock(wlr_surface* pSurface) {
         return false;
 
     for (auto& sls : m_pSessionLock->vSessionLockSurfaces) {
-        if (sls->surface.lock()->surface() == pSurface)
+        if (sls->surface->surface() == pSurface)
             return true;
     }
 
@@ -144,7 +144,7 @@ void CSessionLockManager::removeSessionLockSurface(SSessionLockSurface* pSLS) {
         if (!sls->mapped)
             continue;
 
-        g_pCompositor->focusSurface(sls->surface.lock()->surface());
+        g_pCompositor->focusSurface(sls->surface->surface());
         break;
     }
 }