[Task]: Add a Stop Server Servlet

[hansva]

What needs to happen?

The shutdown of the server was handled by an unprotected web socket listener. Everyone with access to the port could shutdown the server without authentication.

This has currently been disabled for hop 2.7, cleanup the code and add a clean way to shutdown the server via the CLI or url call.

Issue Priority

Priority: 2

Issue Component

Component: Hop Server