[Feature] Add a backend plugin that allows for a GUI server selector

[jacoballen1]

A clear description of the feature you'd like to see implemented

As stated in the title, I would like to add a backend GUI plugin (like you see on many different servers) that can be accessed by either a hub inventory or via the /server command. Either way, this will require a plugin on the backend servers and utilize either plugin messages or Redis in order to transmit data between the proxy and the backend server. (This will also be toggleable via the config, so you don't have to have this plugin enabled to transfer between servers)

[ghost]

Why add this to catalyst, many backend plugins such as commandpannels allow you to quickly create a gui like this on backend servers.