Create initial Steam Store page

[jeroenheijmans]

Some kind of initial Steam Store page with a bare minimum of info and the option to Wishlist the game would be good. It would also be another place to post updates if we want to. It should provide for a slightly smoother launch (if we ever get there) because all wishlisters will get a notification.

First we need to research what a bare minimum Store Page looks like, then we need to add a further to-do list here.

[jeroenheijmans]

Work in progress at the moment!

The Steam Store page is up for initial review. The App Build parts are nearly complete, the Achievements are going into the codebase soon. We'll need to check if builds for non-Steam platforms still work well (there's a no-op implementation of Steam for those platforms).

Steam version forthcoming then.

[jeroenheijmans]

Released!