Switch from Coopstarter to coopedia + fixes on some labels

CONTRIBUTING.md

src/includes/account-creation.pug

src/includes/components/widgets.pug

src/includes/contributor/components/header.pug

src/includes/contributor/profile/create.pug

src/includes/public/components/header.pug

src/includes/searcher/components/header.pug

src/includes/searcher/profile/create.pug

src/scripts/coopstarter.js

src/styles/index.scss