Issue #3081145 by Berdir, andypost, longwave, catch, tim.plunkett, larowlan: Remove BC layers in the Plugin component

Issue #2946122 by mikelutz, heddn, tim.plunkett, phenaproxima, alexpott, joelpittet, MegaChriz, joachim, xjm: Deprecate ConfigurablePluginInterface and replace with an interface that doesn't extend DependentPluginInterface

Revert "Issue #2946122 by mikelutz, heddn, tim.plunkett, phenaproxima, alexpott, MegaChriz, joachim: Deprecate ConfigurablePluginInterface and replace with an interface that doesn't extend DependentPluginInterface"

This reverts commit b1f49624.

Issue #2946122 by mikelutz, heddn, tim.plunkett, phenaproxima, alexpott, MegaChriz, joachim: Deprecate ConfigurablePluginInterface and replace with an interface that doesn't extend DependentPluginInterface

Issue #2923670 by duozersk, Saviktor, joachim: The one-line summary of ImageEffectInterface::getDerivativeExtension() is too long

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #1364670 by mondrake, mrfelton, dinarcon, das-peter, zuuperman, er.pushpinderrana, cchanana, drupaldrop, fietserwin: ImageStyle::transformDimensions unable to deal with all effects

Issue #2420751 by Wim Leers, mondrake, attiks: ImageEffectBase::transformDimensions() should have a sane default implementation

Issue #2330899 by attiks, Jelle_S, fietserwin: Allow image effects to change the MIME type + extension, add a convert image effect.

Issue #2251223 by tim.plunkett: ConfigurableImageEffectInterface should use ConfigurablePluginInterface and PluginFormInterface.