Fellowship whitelisting referendum: https://collectives.subsquare.io/fellowship/referenda/100

Follow the fellowship discussion in https://github.com/polkadot-fellows/runtimes/issues/274

See [`Pallet::dispatch_whitelisted_call_with_preimage`].

- Problem Statement: Lack of whitelisting for fellowship candidates.
- Significance: Ensuring fair access and opportunities for fellowship candidates.
- Proposed Solution: Implementing a whitelisting process for fellowship candidates.
- Expected Outcomes: Increased transparency and inclusivity in the fellowship program.

#680 Initialize Snowbridge on BridgeHub and AssetHub