a lot of improvements

_config.yml

_data/categories/fairex/FAIR_ETH.yml

_data/categories/fairex/FAIR_EUR.yml

_data/form-fairex.yml

_includes/fairex-orders.html

_includes/fairex.html

_includes/form-fairex.html

_includes/form.html

_includes/menu.html

_includes/overview.html

_layouts/default.html

_layouts/selectln.html

assets/js/script.js

css/main.scss

de/fairex.html

de/form-fairex.md

en/fairex.html

en/form-fairex.md