body overflow (horizontal) fix for mobiles

[botweb]

the negative value of right on .langselect lead to an overflow of the body. This caused vertical scrolling on some browser + hides the arrow down to indicate an setting wich the user can change.

[saivann]

@botweb The suggested fix however creates an inconsistent right margin on mobiles, and gives less space for the language name, which makes an existing issue worse; many languages aren't fully displayed (e.g. Users only see "Englis" instead of "English" or "Franç" instead of "Français").

I think we should edit the layout and CSS so the list is displayed in the menu on mobiles to fix all of these issues at once. (See the screenshot below).