Moving 'KStars' to extragear

[Christoph Feck]

Hi,

KStars developers can no longer align to the KDE Applications release 
schedules[1]. Development in KStars happens faster than we release our 
monthly packages.

The result is that since July 2017 several KStars 2.8.x releases were 
announced, that were not available to users using our packages[2]. 
Additionally, bug fixes were since then not committed to the intended 
'KDE Applications/17.08' branch[3].

The referenced bug report shows the confusion this causes to our users.

I had hoped that my comments there could help to find a different 
solution, but given the outcome, I propose to move KStars to 'extragear' 
to allow KStars developers to use a tighter schedule.

If in the future the development can again be aligned, KStars can 
certainly be accommodated again.

[1] https://bugs.kde.org/show_bug.cgi?id=385781#c8
[2] http://knro.blogspot.de/
[3] https://cgit.kde.org/kstars.git/log/?h=Applications/17.08