Dal: manager operation for registering a rollup to a dal slot

Context

• Storage for mapping rollup -> dal_slot_number
• Manager operation for registering a rollup
• Return size storage diff when registering dal slot for rollup (decide later if we want to burn fee for storage) Not applicable after changing storage type.
• Client command for registering a rollup (do we want this to be a command for the L1 or L2 client? It's a layer1 operation, so it should be in layer1 client.)
• RPC to fetch the slot (if any) of a rollup
• Rollup node is able to determine whether to execute in DAL mode or not Rollup node fetches and stores list of subscribed slots during execution.
• RPC in layer2 node to check the execution mode (normal or DAL) fetch the list of slots currently subscribed to
• Unit tests (L1 logic)
• Integration test (rollup node)

Closes: #3057 (closed)

Manually testing the MR

Integration tests:

dune exec tezt/tests/main.exe -- --file sc_rollup.ml --title 'Alpha: integration between dal and scoru node (node_stores_dal_subscriptions)' --verbose

Unit tests:

dune exec src/proto_alpha/lib_protocol/test/unit/main.exe \
      -- test "^\[Unit\] Sc_rollup_storage.ml$"

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