remove introduction sentence. (makes it sound like distros _have_to_ offer...

remove introduction sentence. (makes it sound like distros _have_to_ offer multiple UIs, which they don't)

Interfaces.mw

-As a proper Linux distribution, postmarketOS wants to provide the user multiple interfaces to choose from.
-We try to list each possible interface we can use, and if they require maintenance from our side or not.
-
 This index page could use some help, see {{issue|23|wiki}}.
 
 = Interfaces =