EVM: Kernel: reload the rest of the queue

Context

Contributes to #5873 (closed)

Follows !9369 (merged) and !9682 (merged)

This MR is concerned with finishing the integration of reboot scheduling into the blueprint workflow: the next proposals (as in, those comming after the current one) are stored and reloaded on reboot.

Makes sure that the upgrade mechanism doesn't trigger if a reboot is needed.

Manually testing the MR

Unit test in the kernel.

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR