On restarting/reloading the server establish the connections with database server smoothly

As discussed, I have implemented the feature to reconnect the database server smoothly, whenever we restart/reload the web-application server (pgAdmin IV).

In this implementation, we stores the persistent (auto reconnect) connection information in the session, whenever we connect to/disconnect with the database server. In case of restarting, we fetch that information from the session, and establish the persistent connection(s) for any server.