Before every setting page had the same title and this is causing issues
for screenreaders since they can't differenciate the title of page. Now
a new variable is available for apps to declare the page subtitle.
This new variable is implemented for the settings app and while at it I
added a bit more type hinting to the stuff I touched :)
Signed-off-by: Carl Schwan <carl@carlschwan.eu>
Carl Schwan
John Molakvoæ (skjnldsv)
Christoph Wurst
Morris Jobke
Joas Schilling