Issue #1868772 by tim.plunkett, sun, heyrocker: Convert filters to plugins.

...dules/ckeditor/lib/Drupal/ckeditor/Tests/CKEditorTest.php

core/modules/filter/config/filter.format.plain_text.yml

core/modules/filter/filter.admin.inc

core/modules/filter/filter.api.php

core/modules/filter/filter.module

core/modules/filter/filter.services.yml

core/modules/filter/lib/Drupal/filter/Annotation/Filter.php

core/modules/filter/lib/Drupal/filter/FilterBag.php

...odules/filter/lib/Drupal/filter/FilterFormatInterface.php

...ilter/lib/Drupal/filter/FilterFormatStorageController.php

.../modules/filter/lib/Drupal/filter/FilterPluginManager.php

...ter/lib/Drupal/filter/Plugin/Core/Entity/FilterFormat.php

...es/filter/lib/Drupal/filter/Plugin/Filter/FilterAutoP.php

...les/filter/lib/Drupal/filter/Plugin/Filter/FilterHtml.php

...r/lib/Drupal/filter/Plugin/Filter/FilterHtmlCorrector.php

...lter/lib/Drupal/filter/Plugin/Filter/FilterHtmlEscape.php

...lib/Drupal/filter/Plugin/Filter/FilterHtmlImageSecure.php

...ules/filter/lib/Drupal/filter/Plugin/Filter/FilterUrl.php

core/modules/filter/lib/Drupal/filter/Plugin/FilterBase.php

...dules/filter/lib/Drupal/filter/Plugin/FilterInterface.php