Fix concurrent query module race condition (#1158)

Concurrent access to the same query module had a race condition on the
pointer that was used to handle the custom memory management. With this
commit, a mapping has been added to keep information about what
thread used the pointer to handle the memory resources. This should be
fine since the respected query executions are running on a dedicated
thread. Access to the mapping itself is threadsafe. A simple RAII
wrapper for the mapping container has also been added for simpler
client-side use.

tests/unit/cpp_api.cpp

@@ -27,12 +27,13 @@
 template <typename StorageType>
 struct CppApiTestFixture : public ::testing::Test {
  protected:
-  virtual void SetUp() override { mgp::memory = &memory; }
+  virtual void SetUp() override { mgp::mrd.Register(&memory); }
 
   void TearDown() override {
     if (std::is_same<StorageType, memgraph::storage::DiskStorage>::value) {
       disk_test_utils::RemoveRocksDbDirs(testSuite);
     }
+    mgp::mrd.UnRegister();
   }
 
   mgp_graph CreateGraph(const memgraph::storage::View view = memgraph::storage::View::NEW) {