fix(SW-3691): Setup one prettier config for whole repo
* Setup prettierrc in root and remove other configs
Approved-by: Joakim Jäderberg
Approved-by: Linus Flood
feat(SW-2873): Move BackToTopButton to design-system
* Remove dependency on i18n in BackToTopButton
* Move BackToTopButton to design-system
Approved-by: Hrishikesh Vaipurkar