Issue #2392293 by bircher, tim.plunkett, alexpott, cilefen, gobinathm: Refactor hook_system_info_alter implementations to use ModuleUninstallValidatorInterface

Issue #1810178 by sidharthap, swentel, Xano, Rajesh Ashok, David Hernández, durifal, yched, guy_schneerson: _field_info_collate_fields() is not language-aware, may return wrong values.

Issue #2050835 by Berdir | yched: Move Widget, Formatter, and FieldType plugin types to the Core\Field system.

Issue #1930020 by dawehner, Berdir, olli: Inject a class into the Core annotated discovery implementation so that namespaces can be updated.