Add OpenEntityManagerInView filter for /api/** calls
ArticleQuantityHistory entries now have a reference to the user who created them
Switch to basic auth as the 302 redirect to login form cannot be intercepted by JavaScript code and configure spring security to return a 403 if the request contains wrong or no authentication credentials at all, this prevents the user from popping up the login window (which cannot be suppressed by JavaScript)
Add http interceptor that redirects to login view if the server returned 403
Add login view that sends a dummy request to the server with http basic Authorization header to check if the credentials were valid. The Authorization header is set globally for every http request
Logout button links to the new login view with action=logout, which unsets the global Authorization header again
add explanation
Layout controller added, that hides the navbar links if the user is not logged in
Rename User service to Auth service again
auth service refactored and moved changePassword logic from changePassword controller to the auth service (to update the Auth header with the new password)
auth header is for now persisted in localStorage until token based authentication is implemented