Migrate Mesa server out of API in favour of Mega

[darnfish]

Migrating the Mesa (WebSocket) server from API to a seperate Gateway server, such as Mega would improve performance and remove some off the load from API. With the Mesa Dispatcher API this should be a lot easier to perform and other services like Portals can hook into the pre-existing Mesa server instead of proxying messages to API and then to Mesa.

Also if API goes down briefly during a update then client connections won't be affected and there won't be a sudden surge in load due to authenticating reconnecting clients, which is expensive for the db.

Only issue is it's more to setup for newcomers :/