Display Tetris in Web UI

[soerface]

Currently, the game state of tetris can only be viewed when a user bought a drink (so when he plays).
Add the current status of the Tetris game to website as well. It should be publicly viewable (no login required).

While the block style should be similar to the blocks used in the pygame version, it shouldn't reuse the exact assets, but use proper CSS design that fits the style of the rest of the page.

No need for live updates via JS or whatsover - just a server side rendered HTML like the rest of the page.