MIR: Add commands to test rollup with debugger

Context

Adds means of testing with debugger, which is a lot simpler than doing real deployment.

Depends on !10088 (closed).

Manually testing the MR

Follow the readme (try both make debug-kernel-simple and make debug-kernel-full, the latter is harsh about its prerequisites), check that you see Kernel invoked in the output and that you can see the result written to storage. Try running with

• External message;
• Internal message.

(if after reading the docs and after reading again you don't know how, probably I should clarify them)

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