`about` contains a link to join the Discord server

[TheoPannetier]

I feel the About screen should offer interested players to join and contribute. This could be done via a "Join" button that links to an invite to the Discord server.

For this, we need about to get an invite link, to be passed to about_view later on.

{
    about ab;
    std::vector<std::string> link_to_discord = ab.get_link_discord();
 }

[Luxwor]

its proving really dificult

[OggyOggelito]

There must be a way to dodge the "Expeced unqualified-id"