[Snaps] Secure snapshot sharing

[xmarcalx]

Feature Request

This feature allow to resume different VMs while sharing the same snapshot on the host, reducing the amount of snapshots to store. This issue will track the activities to achieve such goal.

Describe the desired solution

Allow Firecracker to safely boot multiple VM sharing the same snapshot file

Describe possible alternatives

There is currently no alternative which allow firecracker to share safely the same snapshot for multiple VMs to resume.

Additional context

To refine...

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?