#172 Git repository grouping - wip
#172 Type of repository - wip
#172 Precisions about configurations & repositories
#172 Renamed and deprecated the `GitConfiguration` into `FormerGitConfiguration`
#172 New `GitConfiguration` definition as an interface
#172 `BasicGitConfiguration`
#172 `BasicGitConfiguration` as a configuration
#172 `GitHubConfiguration` as a `GitConfiguration`
#172 Getting a `GitRepository` from a `GitConfiguration`
#172 `GitHubConfiguration` management
#172 Migration of configurations in database for GitConfigurations
#172 No GitConfigurator any longer
#172 Starting to replace the former Git configuration object