* Allow changing UmbracoMediaPath to an absolute path. Also ensure Imagesharp are handing requests outside of the wwwroot folder.
* Let UmbracoMediaUrl fallback to UmbracoMediaPath when empty
* Add FileSystemFileProvider to expose an IFileSystem as IFileProvider
* Replace IUmbracoMediaFileProvider with IFileProviderFactory implementation
* Fix issue resolving relative paths when media URL has changed
* Remove FileSystemFileProvider and require explicitly implementing IFileProviderFactory
* Update tests (UnauthorizedAccessException isn't thrown anymore for rooted files)
* Update test to use UmbracoMediaUrl
* Add UmbracoMediaPhysicalRootPath global setting
* Remove MediaFileManagerImageProvider and use composited file providers
* Move CreateFileProvider to IFileSystem extension method
* Add rooted path tests
Co-authored-by: Ronald Barendse <ronald@barend.se>