SCORU/Node: Store migrations

Context

This MR implements a migration mechanism from V0 (store of Mumbai rollup node) to V1 (store format of Nairobi rollup node).

Related to #5554 (closed).

Depends on !8689 (merged), !8687 (merged) and !8691 (merged).

Manually testing the MR

git checkout HEAD~1 # so that the Mumbai rollup node still uses the v0 store
make
dune exec tezt/tests/main.exe -- -f sc_rollup.ml migration -v

The log should show (for the Mumbai->Nairobi migrations):

[09:00:51.995] [sc-rollup-node2] Starting store migration
[09:00:51.995] [sc-rollup-node2] - Migrating store from v0 to v1
[09:00:52.013] [sc-rollup-node2] Store migration completed