Handle case on login if no pw is supplied

In case the user logs in with not password entered the password encryption fails as password was none. No the encryption work with either the supplied password or an empty string.
Added margin for icon images
Configured static paths
Add database connection to earch request

The dbsession is available as db on the request object
Adapted paths the styles.
Added images for used in dropdown menu
Added basic (currently not working testcases)

Test cases for login and logout