Use `SwiftFormat`

[Jasonvdb]

Can you please use SwiftFormat? It has a nice extension that auto-formats on ⌘ S in XCode: SwiftFormat for Xcode.

If anything, to make it simple, we can go with the default config so no time is wasted on configuring it.

Reason:
Trailing and random whitespaces are not nice.

Originally posted by @ovitrif in #8 (comment)

[ovitrif]

Added to project and current sprint, for no other reason than to have it tracked there. Not warranting any urgency, though the sooner the better ;)