Ability to DepositReserveAsset and Transact in one transaction

[xlc]

It will be useful to be able to one transaction to reserve transfer relay chain token to a Parachain, buy weight and execute a Transact.

One use case is support one transaction to transfer KSM from Kusama to Karura and swap it to LKSM to perform staking.

This is not currently possible due to ClearOrigin performed which makes Transact invalid.

One possible way is the ability to fund and transaction with null origin. Or have an instruction to create an account using funds in holding register and transact from this account.