Issue #2298687 by tstoeckler, Jose Reyero, hussainweb, rpayanm: Sequence and Mapping implement interfaces incorrectly, make them honest about what they support

Revert "Issue #2298687 by tstoeckler, Jose Reyero, hussainweb, rpayanm: Sequence and Mapping implement interfaces incorrectly, make them honest about what they support"

This reverts commit 43370336.

Issue #2298687 by tstoeckler, Jose Reyero, hussainweb, rpayanm: Sequence and Mapping implement interfaces incorrectly, make them honest about what they support

Issue #2346129 by tstoeckler: Introduce a TraversableTypedDataInterface and use that for typehinting instead of ArrayElement.

Issue #1866610 by Jose Reyero, Gábor Hojtsy, effulgentsia, alexpott, aspilicious, YesCT, fago, sun, dawehner, heyrocker, yched, spearhead93: Introduce Kwalify-inspired schema format for configuration.