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/protocols/FractionalScale.cpp

@@ -36,8 +36,8 @@ void CFractionalScaleProtocol::onGetFractionalScale(CWpFractionalScaleManagerV1*
         return;
     }
 
-    const auto PADDON = m_mAddons.emplace(surface, std::make_unique<CFractionalScaleAddon>(std::make_shared<CWpFractionalScaleV1>(pMgr->client(), pMgr->version(), id), surface))
-                            .first->second.get();
+    const auto PADDON =
+        m_mAddons.emplace(surface, std::make_unique<CFractionalScaleAddon>(makeShared<CWpFractionalScaleV1>(pMgr->client(), pMgr->version(), id), surface)).first->second.get();
 
     if (!PADDON->good()) {
         m_mAddons.erase(surface);