Allow adding a prexfix to all the routes

[dbrabera]

As a operator of Laika I want to be able to configure a prefix to be added on all routes so I can deploy it under a load balancer that isn't able to route on domains like AWS ALB

Acceptance Criteria

• It is possible to configure a prefix via an environment variable
• The front-side routing accepts the confgured prefix
• The server-side routing accepts the configured prefix