Modifications due to hive.go objectstorage refactor (#306)

* Feat: initial commit

* Feat: Added Consumer model and fixed some smaller issues in Attachment

* Feat: Consumers get stored on transaction arrival

* Feat: added TransactionMetadata to solidifer

* Refactor: started refactoring according to hive.go changes

* Feat: upgrade to latest hive.go

* Fix: fixed some errors after refactor

* Refactor: refactored factory method signature

* Fix: fixed some bugs

* Fix: more fixes

* Fix: fixed some more stuff