refactor: allow for scripts that create notes with multiple assets

[tomyrd]

I think this will create as many notes as there are notes * assets combinations. For now, I think we should assume that each note has only 1 asset and return an error otherwise (for faucets that should always be the case anyway).
The proper way to make this work is to add send_note procedure the BasicWallet interface. This would work similarly to the current send_asset but it would allow creating notes with 0 or more assets.

Originally posted by @bobbinth in #438 (comment)

This issue also requires a new procedure for basic wallets to be implemented first in miden base.