This commit introduces the `TrainingGroup` model and related functionality, allowing for the management of training groups within the application. The `ClubService` is updated to automatically create preset groups upon club creation. The frontend is enhanced with new views and components, including `TrainingGroupsView` and `TrainingGroupsTab`, to facilitate the display and management of training groups. Additionally, the `MembersView` is updated to allow adding and removing members from training groups, improving the overall user experience and interactivity in managing club members and their associated training groups.
7a9e856961