Add SSL to staging and testing

[AlexNi245]

More and more features we build require the client to have an SSL-encrypted connection to the Server. Examples are Browser Notifications, Clipboard, or WebSockets.
To be able to test features involving the things above we need to have SSL on testing and staging as well.

• Add SSL to staging
• Add SSL to testing

It might make sense to keep an eye on #841 and see if it make sense so solve them together.