Add SwiftFormat to the project

[wtimme]

User Story

As a developer, I want the Swift code to be automatically formatted, so that the project has a consistent coding style

Acceptance Criterias

• When building the project, the Swift code is automatically formatted

[wtimme]

With the most recent commits, I have added a configuration file for SwiftFormat that excludes the src/ directory. I think this is a good approach, since the files in the src/ directory are more or less "under control" of the main GoMap repository, and should be formatted there in order to avoid merge conflicts.