Including KDevelop in KDE Gear (for 21.12)

[Friedrich W. H. Kossebau]

Hi,

we would like to switch KDevelop from its own release schedule to KDE Gear, 
starting with 21.12. This includes the following repositories:

* https://invent.kde.org/kdevelop/kdevelop
* https://invent.kde.org/kdevelop/kdev-python
* https://invent.kde.org/kdevelop/kdev-php

This switch to have schedule finding and basic release work provided by the 
good release team workers is to deal with current KDevelop contributors rather 
looking at writing code than planning releases, and should then restore a 
continuous stream of fixes and improvements to the users. And with some 
packagers also help with reaction time on new releases, as they now can plan 
for the whole year.

While KDevelop and the Python & PHP support plugins should be rather mature, 
please still given them a quick sanity check whether the KDevelop bubble has 
not developed too far from what could be considered standard in other KDE Gear 
apps.

Cheers
Friedrich