* Factor out RegistrationCoordinatorLoader
* Add PNI change number state to regcoordinatorloader
* Don't exit change number flow once we start a pni operation
* Add ChangePhoneNumberPniManager to reg coordinator dependencies
* add params required for pni to change number registration mode
* change number from regcoordinator
* rename ChangePhoneNumber -> LegacyChangePhoneNumber
* remove pni change number support from LegacyChangePhoneNumber
* remove codable conformance from pni change number manager's pending state
* Update ts account manager state when finalizing change number
* Add message processor deps to reg coordinator
* addAsyncCompletion on dbv2 write transactions
* Suspend message processing while doing a reg coordinator change number
* hook up change number
* Add handler-free message processing suspension method
* odds and ends
* minor cleanup
* slight refactor to finalize change phone number in the export function
* Put wait for message processing + suspend onto messageProcessor
* kick of prekey refresh after pni change number finalize transaction ends
* nit
* Catch re-entrant MockDBv2 transactions in tests
* Fix some promise + transaction issues in RegCoordinator
* undo dumdum changes; dont handle errors on a guarantee
* Add ability to compute registration recovery password
* Add RegistrationCoordinator
* remove repeat nav controller that evan added
* Scaffolding for RegistrationCoodinator test
* Add first round of RegistrationCoordinator tests, some stuff I needed to get them working, and some fixes to RegistrationCoordinator itself I discovered thanks to the tests
* switch to owsFailBeta
* Add auth credential candidate flow tests, related fixes and additions to coordinator and friends
* Add tests for session based registration path and associated fixes
* PR comment nits
