Prepare routes for guest mode

Description

The following GET routes are now accessible for guest users (see tc-frontend#154). Most of the responses should be compatible with the current app.

Cafeteria

• GET /cafeteria/hours
• GET /cafeteria/{cafeteriaItem}/comments
• GET /cafeteria/{cafeteriaItem}/ratings

Homescreen

• GET /homescreen (Old API) ⚠ returns userId: -2 and order: [1, 5, 4, 8, 6] (default modules)
• GET /modules (New API)

Profile

• GET /profile ⚠ returns displayName: 'Gast' and userName: 'guest' and all badges

Questions & Answers

• GET /questions
• GET /questions/{questionId}
• GET /questions/{questionId}/answers
• GET /questions/categories/{categoryId}
• GET /questions/my-questions returns empty list
• GET /questions/my-replies returns empty list
• GET /questions/user/likes (Deprecated and unused, user-only)
• GET /questions/categories (Deprecated)
• GET /questions/overview

Timeline

• GET /timeline
• GET /timeline/{entryId}
• GET /timeline/faved
• GET /timeline/pinned
• GET /timeline/pinned/all (Deprecated)
• GET /timeline/pinned/unpin (Deprecated and currently not used in lib/, only in test/, now user-only)
• GET /timeline/sources/settings