Better auth user/role handling (#1699)

* Stop auth module from creating users
* Explicit about auth policy (check if no users defined OR auth module used)
* Role supports database access definition
* Authenticate() returns user or role
* AuthChecker generates QueryUserOrRole (can be empty)
* QueryUserOrRole actually authorizes
* Add auth cache invalidation
* Better database access queries (GRANT, DENY, REVOKE DATABASE)

src/query/interpreter.hpp

@@ -210,7 +210,7 @@ class Interpreter final {
     std::optional<std::string> db;
   };
 
-  std::optional<std::string> username_;
+  std::shared_ptr<QueryUserOrRole> user_or_role_{};
   bool in_explicit_transaction_{false};
   CurrentDB current_db_;
 
@@ -300,7 +300,7 @@ class Interpreter final {
 
   void ResetUser();
 
-  void SetUser(std::string_view username);
+  void SetUser(std::shared_ptr<QueryUserOrRole> user);
 
   std::optional<memgraph::system::Transaction> system_transaction_{};