Issue #2233787 by alexpott, xjm | tim.plunkett: Move default configuration into extension/config/install to clarify its purpose.

Issue #2098119 by beejeebus, alexpott, chx: Replace config context system with baked-in locale support and single-event based overrides.

Issue #1763640 by beejeebus, alexpott, Jose Reyero, c31ck, das-peter, YesCT, heyrocker, Gábor Hojtsy: Introduce config context to make original config and different overrides accessible.