effects: Port EffectFrame to OffscreenQuickView

This allows to toss a large amount of custom rendering code.

Furthermore, it removes the build-time dependency on Plasma Framework
for FrameSvg and Theme from KWin core as it's pulled in through QML
imports now.

It also cleans up the API and removes functions that are effectively
unused or no-op after this change.

For instance, effects often destroy their effect frames
in pre/postPaintScreen, which would now destroy an `OffscreenQuickView`,
which changes GL context. This is alleviated by delaying detruction
of the internal view.

Support for the features of text cross-fade and selection frame,
which are not used by any of the built-in effects, is dropped.

Signed-off-by: Eike Hein <eike.hein@mbition.io>