Record trigger execution as a transaction

[mversic]

Financial applications need to track the flow of assets. It has been noted that trigger execution isn't transactional. If a trigger is invoked and it transfers asset from user A to user B this is hard to track (for blockchain explorers) unless the trigger also makes a record in the metadata.

This doesn't mean that blockchain state is ever inconsistent across peers. If the whole blockstore is replayed then every peer will reach the same state, but no transactions will be recorded for trigger executions.

I'm not sure whether we should change this behavior. Maybe we can make it so that every trigger execution is recorded as a transaction in a block. This means that the leader will inject the appropriate transactions when constructing a block and all other peers will also verify that indeed a correct transaction was injected