Several backend db migrations that fix state of the chain:
- Bumping StorageVersion for pallets TransactionPayment, History, Scheduler, Multisig, Staking. Otherwise no functional changes for those pallets.
- Removing 6 nomination pools that are still on outdated V1 schema.
- Migrating V2 to V3 schema for all nomination pools.
- Migrating all contracts from V7 to V8 version