Add context information to the structured logs for requests

After #9 (closed) is implemented, we keep track of context information in a request:

• The user performing the request
• The project / namespace to which the request is targeted.

We currently use this information to add this to the sidekiq logs. But we could also include this information when writing to the production_json.log for rails requests by adding this to the lograge initializer.

To add this information to API requests, we could add an extra logger for Grape that includes this information.