Refactor HostDescriptor::open_at for VfsCtxView to allow writes #336
Description
What
As part of #133, we'll need to be able to allow guests to perform open operations on VFS nodes on the host fs. This is necessary to further facilitate FS writes. Refactor the HostDescriptor::open_at trait method (it currently only handles reads) for VfsCtxView.
Be sure to include a unit test that uses the open_at method and fix any broken integration tests to reflect the new VFS behavior.