Deleted Inodes with open filehandles aren't explicitely handled

Currently, when a file is deleted, it is immediately removed and no trace is left.
Still active FDs can be used, but will most likely fail with ENOENT or InodeNotFound.

From what I can find online, the correct way to handle this is that delete only removes the **name** from the parent folder, and not the actual file or inode.
The inode would be automatically deleted when its last name or fd is dropped, like a smart pointer

This might be relevant to @iddeko's current work on #112 with tracking of file handles

Currently, the shell builtin mv tries to getattr after the rename. This creates an ERROR in the logs, but mv is quitely ignoring the failure so there's no real effect in this case. Other common use cases could be more problematic