* feat: new rest api based on the current store json-rpc api and
following the same structure as the current relay rest api.
* feat: the store api attend GET requests to retrieve historical messages
* feat: unit tests.
* feat: allow return message to rest-client in case error (4XX or 5XX)
* chore: always allow to call the store api endpoints (only rest) without explicit storenode (#1575)
* feat: always mounting the current node as storenode client
