Add url prefix to react frontend

[Fattigman]

The base path of the URL should be easily modifiable, in order to host the application on a local server with several applications already hosted there. Otherwise, the application's HTTP responses to the server will route to the wrong URLs.

Like so:

localhost:3000/<ROOT_PATH>

One way to do it would be to add an environment variable to the docker-compose.yml file. This environment variable is then used in the frontend application to set the prefix at the application level.

This issue can be closed when:

• [ ] The front-end URL can easily be prefixed.

[moedarrah]

https://github.com/genomic-medicine-sweden/docker-sc2reporter/pull/108

[moedarrah]

Done!