A guest or an authenticated user can see details of a question

[josepostiga]

Scenario

Given I'm an authenticated user of any type
When I send a GET request to /discussions/questions/{questionId}
I expect to see the details of the given question

Given I'm a guest user
When I send more than 30 GET requests to /discussions/questions/{questionId} within a single minute
I expect to receive a 429 Too Many Requests status code until the next minute

Additional requirements

This builds on the features of #25.

[dleicam]

Solved with PR #49