Create a scheduler for validation of the block

In the parallel-executor the scheduler for production is performing operations to order transactions in different batches that could be executed in the same time, making sure we don't collide on contracts, waiting on transaction source etc...

In order to make the most optimized version, the validation of the block can be performed without some of these operations because we can assume that:
- We already have all transactions of the block
- That they are already in a correct order (otherwise we fail the validation which is expected)
- ...