We use `fs.unlink` instead of `fs.rm`, as the latter is only available in the fsPromises API since Node 14.14
Signed-off-by: David Mehren <git@herrmehren.de>
This backend stores uploaded media into files on the local filesystem.
This commit also adds a `BackendType` enum, which can be used to distinguish different media backends.
Signed-off-by: David Mehren <git@herrmehren.de>