Add dispatchables for root origin

[mattsse]

Issue summary

• current saftregistry and assetindex require the origin to be signed, to mint/burn from the sender's account. This prevents us from using Root to execute this calls. Therefore
• Add additional force_* dispatchables (add_asset, add_saft, remove_asset) that mirror the existing ones but take an additional recipient parameter and ensure_root. For example fn force_add_asset(..., recipient: AccountId) {ensure_root(origin)?;}

Other information and links

• Ref Fix benchmarks for pallet asset-index and pallet saft-registry #317

[Redoudou]

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