Merge branch '5.4'

diff --cc com.woltlab.wcf/mediaProvider.xml
Simple merge

diff --cc ts/WoltLabSuite/Core/Ui/Message/Quote.ts
Simple merge

diff --cc wcfsetup/install/files/js/WoltLabSuite/Core/Acp/Ui/User/Content/Remove/Handler.js
Simple merge

diff --cc wcfsetup/install/files/js/WoltLabSuite/Core/Ui/Message/Share/Dialog.js
Simple merge

diff --cc wcfsetup/install/files/lib/system/WCF.class.php
Simple merge

diff --cc wcfsetup/install/files/lib/system/devtools/package/DevtoolsPackageXmlWriter.class.php
Simple merge

diff --cc wcfsetup/install/files/lib/system/form/builder/field/acl/AclFormField.class.php
Simple merge

diff --cc wcfsetup/install/files/style/ui/contentItem.scss
Simple merge

diff --cc wcfsetup/install/lang/de.xml
Simple merge