New Transaction Queue implementation (#8074)

* Implementation of Verifier, Scoring and Ready.

* Queue in progress.

* TransactionPool.

* Prepare for txpool release.

* Miner refactor [WiP]

* WiP reworking miner.

* Make it compile.

* Add some docs.

* Split blockchain access to a separate file.

* Work on miner API.

* Fix ethcore tests.

* Refactor miner interface for sealing/work packages.

* Implement next nonce.

* RPC compiles.

* Implement couple of missing methdods for RPC.

* Add transaction queue listeners.

* Compiles!

* Clean-up and parallelize.

* Get rid of RefCell in header.

* Revert "Get rid of RefCell in header."

This reverts commit 0f2424c9b7319a786e1565ea2a8a6d801a21b4fb.

* Override Sync requirement.

* Fix status display.

* Unify logging.

* Extract some cheap checks.

* Measurements and optimizations.

* Fix scoring bug, heap size of bug and add cache

* Disable tx queueing and parallel verification.

* Make ethcore and ethcore-miner compile again.

* Make RPC compile again.

* Bunch of txpool tests.

* Migrate transaction queue tests.

* Nonce Cap

* Nonce cap cache and tests.

* Remove stale future transactions from the queue.

* Optimize scoring and write some tests.

* Simple penalization.

* Clean up and support for different scoring algorithms.

* Add CLI parameters for the new queue.

* Remove banning queue.

* Disable debug build.

* Change per_sender limit to be 1% instead of 5%

* Avoid cloning when propagating transactions.

* Remove old todo.

* Post-review fixes.

* Fix miner options default.

* Implement back ready transactions for light client.

* Get rid of from_pending_block

* Pass rejection reason.

* Add more details to drop.

* Rollback heap size of.

* Avoid cloning hashes when propagating and include more details on rejection.

* Fix tests.

* Introduce nonces cache.

* Remove uneccessary hashes allocation.

* Lower the mem limit.

* Re-enable parallel verification.

* Add miner log. Don't check the type if not below min_gas_price.

* Add more traces, fix disabling miner.

* Fix creating pending blocks twice on AuRa authorities.

* Fix tests.

* re-use pending blocks in AuRa

* Use reseal_min_period to prevent too frequent update_sealing.

* Fix log to contain hash not sender.

* Optimize local transactions.

* Fix aura tests.

* Update locks comments.

* Get rid of unsafe Sync impl.

* Review fixes.

* Remove excessive matches.

* Fix compilation errors.

* Use new pool in private transactions.

* Fix private-tx test.

* Fix secret store tests.

* Actually use gas_floor_target

* Fix config tests.

* Fix pool tests.

* Address grumbles.