Add support for replacing a file from the UI and API.
Introduce new webhook AfterFileReplaced for when a file have been replaced, see event page for payload.
Note: file references in PIM will not be updated (support is work in progress)
Note: any references to files which have been replaced will need to be updated as the replaced file no longer exists in DAM. The CDN will redirect to the new file. The old file may be served until the cache expires.