Flashtestation Transaction In Every Flashblock

Currently we only put the flashtestation transaction at the end of each **regular **block** every 1 second, rather than in every flashblock every 200ms. This has the downside that users who work with flashblocks rather than regular blocks will not be able to verify their blocks are fairly built until a regular block gets published.

@Ruteri had written up a doc discussing different options we have for putting a flashtestation tx in every flashblock, so we should consult that, decide on a design, and implement it

Start by finding and reading the options document written by @Ruteri, then determine which design the project will use for adding a flashtestation transaction to every flashblock. Done means flashblocks published every 200ms contain the transaction and users can verify that each block was fairly built before the regular block is published.

Written by the indexing model from the issue text.