[Snaps] Allow resource renaming during snapshot restore

[pb8o]

Feature Request

In the past we have received several requests to add the ability to rename devices during snapshot restore. This is useful for example for TAP devices when not using network namespaces, or changing paths when not using a chroot.

Describe the desired solution

Add support for overriding devices. There is already one open PR about it for network TAP devices in #4731.

The Firecracker team will support this effort by providing code reviews, and making sure the changes fit our design for the snaphshot-restore feature, but we don't plan to work on it at the moment, so development of this feature will be community-driven.

Describe possible alternatives

The alternatives already exist, for example using network namespaces or mount namespaces. This adds an alternative when it's not possible or practicel.

Additional context

See #4014, #4731.

Checks

• [x] Have you searched the Firecracker Issues database for similar requests?
• [x] Have you read all the existing relevant Firecracker documentation?
• [x] Have you read and understood Firecracker's core tenets?