* Implemented offer validation interface.
* Implement high level offer validation steps.
* Completed state validation tests.
* Update validation to use result type.
* Update state proof verification tests to test offer verification.
* Query history network to get state root by block hash.
* Fix state network test and remove usage of CoreDb.
* Fix state network gossip test and PR comment updates.
* Add trieproof state validation tests and fix for short nodes.