Run server.closeAllConnections() before server.close()

[andygout]

This PR addresses an issue that was encountered on another Node.js app with a Neo4j database in which after a change was made to the code which triggered a Nodemon restart of the server, it would be impossible to close the server using ctrl + c and would require that the entire CLI shell was closed.

Upon the sixth attempt at ctrl + c, the following message would appear:

(node:26548) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 close listeners added to [Server]. Use emitter.setMaxListeners() to increase limit
(Use node --trace-warnings ... to show where the warning was created)

Each attempt of ctrl + c would call server.close() twice (but not invoke the callback), so the sixth attempt would reach the 11th call, indicating that each call would add a close listener.

I'm not sure of the exact cause, but the below references helped lead me to a solution.

References:

• Node.js: server.closeAllConnections()
• Stack Overflow: Why is server.close callback never invoked?
• Stack Overflow: Force close all connections in a node.js http server
• GitHub: nodejs/node — Issues: Add ability to force close persistent connections