title: Adds `BlockNumberProvider` in multisig, proxy and nft pallets

doc:
  - audience: Runtime Dev
    description: |
      This PR adds the ability for these pallets to specify their source of the block number.
      This is useful when these pallets are migrated from the relay chain to a parachain and 
      vice versa.

      This change is backwards compatible:
      1. If the `BlockNumberProvider` continues to use the system pallet's block number
      2. When a pallet deployed on the relay chain is moved to a parachain, but still uses the 
      relay chain's block number

      However, we would need migrations if the deployed pallets are upgraded on an existing parachain,
      and the `BlockNumberProvider` uses the relay chain block number.  

crates:
  - name: pallet-multisig
    bump: major
  - name: pallet-proxy
    bump: major
  - name: pallet-nfts
    bump: major