Merge branch '3476981-5.1.0-use-icons' into '5.1.x'

assets/css/component/icons.css

assets/css/media-library/media-library-icons.css

composer.json

src/Element/ElementPreRenderLink.php

src/Element/ElementProcessTextFormat.php

src/HookHandler/ElementInfoAlter.php

src/HookHandler/FormMediaLibraryAddFormAlter.php

src/HookHandler/PreprocessMediaLibraryItem.php

src/HookHandler/PreprocessMenuLocalAction.php

src/HookHandler/PreprocessViewsView.php

src/HookHandler/PreprocessViewsViewTable.php

src/Utility/Bootstrap.php

src/Utility/Element.php

templates/system/feed-icon.html.twig

templates/system/tablesort-indicator.html.twig

ui_suite_bootstrap.api.php

ui_suite_bootstrap.icons.yml

ui_suite_bootstrap.info.yml

ui_suite_bootstrap.libraries.yml

ui_suite_bootstrap.theme