Add route cards to the routes page

[ketnek]

Value proposition

As a user I want to see my created routes on the routes page in order to have a nice overview about them.

Description

Acceptance criteria

• [ ] Clicking the routes icon in the nav bar opens the routes page and shows all created routes

Tasks

• [ ] Create a new feature branch
• [ ] Create a GET method to query the data from the mongoDB
• [ ] Create a RouteCard component that renders the saved routes

[cmgoersch]

LGTM :)