Remove java code not related to providing js to browser

[retog]

This project should just be the js frontend, with minimal to deliver an html resource with the script, so basically the state at: https://github.com/fusepool/fusepool-firstswim/tree/40b6dc2abed6bf24c7cbde3ead5189ee14b79528/src/main/java/eu/fusepool/firstswim

All other services should be provided by the modules providing the functionality.