Private transactions integration pr (#6422)

* Private transaction message added

* Empty line removed

* Private transactions logic removed from client into the separate module

* Fixed compilation after merge with head

* Signed private transaction message added as well

* Comments after the review fixed

* Private tx execution

* Test update

* Renamed some methods

* Fixed some tests

* Reverted submodules

* Fixed build

* Private transaction message added

* Empty line removed

* Private transactions logic removed from client into the separate module

* Fixed compilation after merge with head

* Signed private transaction message added as well

* Comments after the review fixed

* Encrypted private transaction message and signed reply added

* Private tx execution

* Test update

* Main scenario completed

* Merged with the latest head

* Private transactions API

* Comments after review fixed

* Parameters for private transactions added to parity arguments

* New files added

* New API methods added

* Do not process packets from unconfirmed peers

* Merge with ptm_ss branch

* Encryption and permissioning with key server added

* Fixed compilation after merge

* Version of Parity protocol incremented in order to support private transactions

* Doc strings for constants added

* Proper format for doc string added

* fixed some encryptor.rs grumbles

* Private transactions functionality moved to the separate crate

* Refactoring in order to remove late initialisation

* Tests fixed after moving to the separate crate

* Fetch method removed

* Sync test helpers refactored

* Interaction with encryptor refactored

* Contract address retrieving via substate removed

* Sensible gas limit for private transactions implemented

* New private contract with nonces added

* Parsing of the response from key server fixed

* Build fixed after the merge, native contracts removed

* Crate renamed

* Tests moved to the separate directory

* Handling of errors reworked in order to use error chain

* Encodable macro added, new constructor replaced with default

* Native ethabi usage removed

* Couple conversions optimized

* Interactions with client reworked

* Errors omitting removed

* Fix after merge

* Fix after the merge

* private transactions improvements in progress

* private_transactions -> ethcore/private-tx

* making private transactions more idiomatic

* private-tx encryptor uses shared FetchClient and is more idiomatic

* removed redundant tests, moved integration tests to tests/ dir

* fixed failing service test

* reenable add_notify on private tx provider

* removed private_tx tests from sync module

* removed commented out code

* Use plain password instead of unlocking account manager

* remove dead code

* Link to the contract changed

* Transaction signature chain replay protection module created

* Redundant type conversion removed

* Contract address returned by private provider

* Test fixed

* Addressing grumbles in PrivateTransactions (#8249)

* Tiny fixes part 1.

* A bunch of additional comments and todos.

* Fix ethsync tests.

* resolved merge conflicts

* final private tx pr (#8318)

* added cli option that enables private transactions

* fixed failing test

* fixed failing test

* fixed failing test

* fixed failing test