Look into what it'll take to add more unit tests for the store handlers

[joe94]

We need to test the handlers https://github.com/xmidt-org/argus/blob/main/store/handler.go

Themis might be a good example to follow: https://github.com/xmidt-org/themis/tree/main/token where the encoders/decoders are placed in a transport.go file