Introduce a new config entry into kdeglobals AnimationSpeed that will
control /all/ animation speeds in kwin and plasma themes and Qt styles
The value stored is a multiplier.
i.e 1 == normal speed, 0.5 = twice as fast, 2 = twice as slow.
0 is a special value meaning "disable animations"
The QML is a bit complex to represent a logarithmic slider that goes
4x, 2x, 1x, 0.5x, 0.25x, 0.125x
but still allowing a user to type arbitrary values into their config
Note @kbroulik This is reversed it from what we coded together, because
I decided it was confusing.
Needs relevant patches through the rest of the stack before merging.
Also kwin has some asserts on 0 speed animations that need addressing.
You also need an up-to-date kconfig and qqc2-desktop-style for bugfixes