Issue #3414291 by pdureau, Christian.wiedemann: Source plugins, methods naming and interfaces use

...es/ui_patterns_blocks/src/Plugin/Block/ComponentBlock.php

...ui_patterns_layouts/src/Plugin/Layout/ComponentLayout.php

modules/ui_patterns_layouts/ui_patterns_layouts.module

modules/ui_patterns_legacy/ui_patterns_legacy.module

src/ComponentPluginManager.php

src/Element/ComponentElementAlter.php

src/Element/ComponentElementBuilder.php

src/Element/ComponentForm.php

src/Element/ComponentFormBase.php

src/Element/ComponentPropsForm.php

src/Element/ComponentSlotsForm.php

src/Form/ComponentFormBuilderTrait.php

src/Form/ComponentSettingsFormBuilderTrait.php

src/Plugin/UiPatterns/Source/AttributesWidget.php

src/Plugin/UiPatterns/Source/ChecboxesWidget.php

src/Plugin/UiPatterns/Source/CheckboxWidget.php

src/Plugin/UiPatterns/Source/ColorWidget.php

src/Plugin/UiPatterns/Source/ListTextareaWidget.php

src/Plugin/UiPatterns/Source/MenuSource.php

src/Plugin/UiPatterns/Source/NumberWidget.php