Introduce network simulation to DAL's tezt cloud scenario

This MR introduces the --simulate x,y parameters that aims to allow retrieving the x active bakers from the given snapshot of a real-network, share their baking keys across y actual bakers and run the DAL tezt cloud test.

Manually testing the MR

If you want to simulate a ghostnet network with 2 produces, 2 bakers sharing the 30 biggest baking keys of ghostnet, run:

dune exec tezt/tests/cloud/main.exe -- DAL --producers 2 --producer-slot-indices 9,10 --log-file ghostnet-producers.log --network sandbox --tezt-cloud ghostnet-1-producers --dockerfile-alias dal --keep-temp -v --localhost --snapshot ./recent_ghostnet_snapshot.rolling --simulate map(30,3)

⚠️ Running this test locally requires a tremendous amount of RAM: ~150Gb

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