Perform loadgen tasks with installed asset

[mhofman]

Agoric/agoric-sdk#4541 removed the ability to collateralize RUN, and subsequently Agoric/agoric-sdk#4165 removed sample tokens from being usable in vaults, removing them as known assets for trading as well. See Agoric/agoric-sdk#4634

The approach forward is likely for the loadgen to install a contract which mints its own asset, bless that issuer to be used as collateral, and create a pool for the amm. This will require provisioning the chain configuring it with the solo address of the loadgen that can get the vault creator facet. See Agoric/agoric-sdk#4641

This approach may be backwards compatible if previous SDK revisions don't need, or have an alternate mechanism to bless issuers for usage as collateral. (Try to perform both and only fail if neither succeeds)