Merge branch '1139-renew-the-help-page' into 'development'

public/img/app-grau.svg

public/img/back-arrow.svg

public/img/bangs-icon-help.svg

public/img/capitalization-icon-help.svg

public/img/cookies.svg

public/img/icon-settings-grau.svg

public/img/jugendschutz.svg

public/img/lupe-grau.svg

public/img/maps-grau.svg

public/img/proxy.svg

public/img/result-icon-help.svg

public/img/searchfield-icon-help.svg

public/img/searchinsearch-icon-help.svg

public/img/startseite-icon-help.svg

public/img/stopwords-icon-help.svg

public/img/suchwortasso.svg

public/img/tor-icon.svg

public/img/url-icon-help.svg

public/img/widget.svg

resources/lang/de/help/help-functions.php