Release Notes Datahub 0.5 published on the Datahub pages

News body: 

Published document includes the release notes for the Fingrid Datahub version 0.5 (Stage 5). The document describes the implemented functionalities, existing / resolved deviations and defects in the release. Release includes a B2B message interface using SOAP and a web browser GUI portal.

Link to the Datahub 0.5 Release Notes