Decoding incarnation implemented (#2764)

* WIP decoding incarnation specifically

* Changed decodeIncarnation to be an external function

* added tests to for decoding incarnations

* ran gofmt -w -s

* changed test name, and changed incarnations to 4

* Created a test which tests if it returns an error when there is one

* ran gofmt

* Capitalized all tests and made breaking test

* added an error check

* changed decodingForStorage for decodingIncarnationFromStorage

* ran gofmt -w -s