feat: HTML structure redesigned.

#48

refactor: workaround damit mir das ding nicht um die ohren fliegt. (bleibt so bis michael das ganze behoben hat)

feat: Login and register site type works.

feat: Currency Lang Switch reworked. Do not show arrow if there are nothing to switch (neither language nor currency)

refactor: Many small changes.
fix: Search on product search site works.

feat: Clear filter button styled.

refactor: Class documentation changed.

feat: Payments control added.

feat: Many others shop category menu improvements.

feat: New template settings (show / hide shop categories menu).