Write guide "Set up The Lounge as a standalone application"

[xPaw]

• Depends on OS/Browser
• New Chrome versions require HTTPS (with trusted cert) on common port (443, 8443, maybe others?)

[astorije]

Will add this when taking over the docs.

[xPaw]

I wrote some text some time ago, I'll post it here so it's not lost:

The Lounge is a progressive web application and supports many features one would expect from a native application, including push notifications. Making a native application would require double the amount of work to create and maintain, thus it makes more sense to maintain a single web application that works anywhere.
Currently push notifications do not work on iOS because Safari does not support web push specification.
Adding The Lounge to home screen allows the app to appear just like a native one.