ValueTangle implementation (#320)

* Feat: refactored message + started to add tests

* Refactor: go mod tidy

* Refactor: continued to refactor message

* Feat: updated to last hive.go + added Signature() methid

* Feat: go mod tidy

* Feat: added mutex to the signature write in Bytes()

* Fix: fixed Signature method

* Feat: refactored message methods

* Feat: refactored output

* Fix: fixed signature mismatch in tangle factory methods

* Refactor: go mod tidy

* Feat: added solditification logic to value tangle

* Feat: fixed some code related to objectstorage factories