Closes #128 (closed)

Proposed changes

• Implement HTTP Interceptor
  • Adds the JWT token to any request, if available (when logged in, for example)
  • No further actions needed to send jwt headers
• Implement guest login and usual login

IMPORTANT

This MR will change a basic functionality in the project. Merging this will delete the in-memory-data-service. This means that all the requests to the old, local db will crash unless it is already changed to the new api routes of the ARSnova backend

Use this branch as the base branch for further api changes!

If you want to work at any api issue, use THIS BRANCH as base branch! This branch will be merged along with all other api branches as soon as they are all ready!

ToDo

• Add register route (old api)
• Add password reset route (old api)
• Add error handling to interceptor